Saturday, January 9, 2010

toothpick sequences

New article:
http://www.scipress.org/journals/forma/frame/24.html
/Then click on to No.2

Date: Thu, 7 Jan 2010 20:23:26 -0800
From: qntmpkt@yahoo.com
Subject: Toothpick / Tetrahedral "closed walks" - proof - Gary

proof of the generalization should be within each reach, where we state that:
...
Theorem: (toothpick sequence )/ ("tends to" sequence of triangle rows) = corresponding "closed walks of length n along edges of (tetrahedron, etc) based at vertex.
First, by way of example, let's cover the left side of the equation.
Given our triangle A160552:
1
1, 3
1, 3, 5, 7
1, 3, 5, 7, 5, 11 17, 15;
...
where rows tend to A151548: (1, 3, 5, 7, 5, 11 17, 15, 5, 11, 17, 15, 5, 11, 17, 19,...).
Already in your comments section, we have triangle (A160552) as a string * (1, 2, 2, 2, ....) = toothpick, sequence A139250. But
(A160552) * (1, 2, 0, 0, 0, ...) = A151548., the "tends to" sequence.
So we put
A160552 * (1, 2, 2, 2,...) / A160552*(1, 2, 0, 0, 0,...); = (toothpick / "tends to"); then the A160552 cancels., leaving
(1, 2, 2, 2,...) / (1, 2, 0, 0, 0,...).
...
Now we cover the right side of the equation by listing some examples. Case N=1 turns out to be (1, 0, 1, 0, 1, 0, 1,...) trivial.
So next we address A151575: (1, 0, 2, -2, 6, -10, 22, -42, 86,...). But first we access the unsigned version:
(1, 0, 2, 2, 6, 10, 22, 42, 86,....); noting that the g.f. is
(1-x) / (1 - x - 2x^2).
It can be shown that the signed version =
(1, 2, 2, 2,....) / (1, 2, 0, 0, 0,...).; so the previous formula should be tweaked to reflect the alternating signs.
But (1, 2, 2, 2,...) / (1, 2, 0, 0,....) is what we had before on the left side of the formula. Proof is complete for this case N=2.
...
Next, case N=3: Right side of the formula is A054878: (1, 0, 3, 6, 21, 60 183, 546, 1641,...) but with alternating signs.
A054878 g.f. is (1 - 2x)/ (1-2x-3x^2) where from the previous g.f. we just add "1" to coeff of x's. it can be shown that the alternating sign version of A054878 = (1, 3, 3, 3,....) / (1, 3, 0, 0, 0); where again this = (toothpick seq N=3) / ("tends to" sequence); where the generating triangle for N=3 =
1
1, 4
1, 4, 7, 13;
1, 4, 7, 13, 7, 19, 34, 40;
... again left side of equation = right side.
....
Next, case N=4, right side of equation = A109499: (1, 0, 4, 12, 52, 204, 820, 3276,...) where we just add "1" to coeff of x (but the entry has a slightly different formula. Anyway, the same formatted formula would be (1 - 3x) / (1 - 3x - 4x^2). But we want the version with alternate signs, so that formula can be tweaked to equate to:
(1, 4, 4, 4,....) / (1, 4, 0, 0, 0).; proof should follow.
Next, case N=5 = A109500: (1, 0, 5, 20, 105, 520, 2605, 13020,...); and the analogous formula should be:
(1 - 4x) / (1 - 4x - 5x^2); with the alternating sign version =
(1, 5, 5, 5,...) / (1, 5, 0, 0, 0,...). proof should follow.
...
...but I'm not into proofs so you can have this project, if desired.
...Gary



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New article:
http://www.scipress.org/journals/forma/frame/24.html
/Then click on to No.2

Date: Thu, 7 Jan 2010 20:23:26 -0800
From: qntmpkt@yahoo.com
Subject: Toothpick / Tetrahedral "closed walks" - proof - Gary

proof of the generalization should be within each reach, where we state that:
...
Theorem: (toothpick sequence )/ ("tends to" sequence of triangle rows) = corresponding "closed walks of length n along edges of (tetrahedron, etc) based at vertex.
First, by way of example, let's cover the left side of the equation.
Given our triangle A160552:
1
1, 3
1, 3, 5, 7
1, 3, 5, 7, 5, 11 17, 15;
...
where rows tend to A151548: (1, 3, 5, 7, 5, 11 17, 15, 5, 11, 17, 15, 5, 11, 17, 19,...).
Already in your comments section, we have triangle (A160552) as a string * (1, 2, 2, 2, ....) = toothpick, sequence A139250. But
(A160552) * (1, 2, 0, 0, 0, ...) = A151548., the "tends to" sequence.
So we put
A160552 * (1, 2, 2, 2,...) / A160552*(1, 2, 0, 0, 0,...); = (toothpick / "tends to"); then the A160552 cancels., leaving
(1, 2, 2, 2,...) / (1, 2, 0, 0, 0,...).
...
Now we cover the right side of the equation by listing some examples. Case N=1 turns out to be (1, 0, 1, 0, 1, 0, 1,...) trivial.
So next we address A151575: (1, 0, 2, -2, 6, -10, 22, -42, 86,...). But first we access the unsigned version:
(1, 0, 2, 2, 6, 10, 22, 42, 86,....); noting that the g.f. is
(1-x) / (1 - x - 2x^2).
It can be shown that the signed version =
(1, 2, 2, 2,....) / (1, 2, 0, 0, 0,...).; so the previous formula should be tweaked to reflect the alternating signs.
But (1, 2, 2, 2,...) / (1, 2, 0, 0,....) is what we had before on the left side of the formula. Proof is complete for this case N=2.
...
Next, case N=3: Right side of the formula is A054878: (1, 0, 3, 6, 21, 60 183, 546, 1641,...) but with alternating signs.
A054878 g.f. is (1 - 2x)/ (1-2x-3x^2) where from the previous g.f. we just add "1" to coeff of x's. it can be shown that the alternating sign version of A054878 = (1, 3, 3, 3,....) / (1, 3, 0, 0, 0); where again this = (toothpick seq N=3) / ("tends to" sequence); where the generating triangle for N=3 =
1
1, 4
1, 4, 7, 13;
1, 4, 7, 13, 7, 19, 34, 40;
... again left side of equation = right side.
....
Next, case N=4, right side of equation = A109499: (1, 0, 4, 12, 52, 204, 820, 3276,...) where we just add "1" to coeff of x (but the entry has a slightly different formula. Anyway, the same formatted formula would be (1 - 3x) / (1 - 3x - 4x^2). But we want the version with alternate signs, so that formula can be tweaked to equate to:
(1, 4, 4, 4,....) / (1, 4, 0, 0, 0).; proof should follow.
Next, case N=5 = A109500: (1, 0, 5, 20, 105, 520, 2605, 13020,...); and the analogous formula should be:
(1 - 4x) / (1 - 4x - 5x^2); with the alternating sign version =
(1, 5, 5, 5,...) / (1, 5, 0, 0, 0,...). proof should follow.
...
...but I'm not into proofs so you can have this project, if desired.
...Gary



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Triangle Bikini
Get ready for the summer. Shop for bikinis at Become!
Trading with Triangles
Free issue! Stocks & Commodities magazine. How-to guide for traders.
Geometry for grades K-6
Practice area, volume, perimeter, shape names, terms, so much more!
Geometry Shapes
All About Geometry Shapes Geometry Shapes and Much More!
Math problems?
Let us help you
It is free
Math Manipulatives
The multi-sensory math programme that is transforming math teaching
"Raise Your Credit Score"
"I Raised My Bad Credit Score To Over 725 Using These Free Tips!"
Math Tutoring
Salt Lake City math tutoring. Find local businesses on DexKnows.
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