A136337 Triangular sequence from both a quartic expansion polynomial and a four deep polynomial recursion: Expansion polynomial: f(x,t)=1/(1 - 2*x*t + t^4); Recursion polynomials: p(x, n) = 2*x*p(x, n - 1) - p(x, n - 4);.

1, 0, 2, 0, 0, 4, 0, 0, 0, 8, -1, 0, 0, 0, 16, 0, -4, 0, 0, 0, 32, 0, 0, -12, 0, 0, 0, 64, 0, 0, 0, -32, 0, 0, 0, 128, 1, 0, 0, 0, -80, 0, 0, 0, 256, 0, 6, 0, 0, 0, -192, 0, 0, 0, 512, 0, 0, 24, 0, 0, 0, -448, 0, 0, 0, 1024

Offset

1,3

Comments

Row sums are A008937.

This sequence was a designed experiment in Umbral Calculus

using a quartic polynomial for the expansion base.

I was testing the recursion form in the polynomial as:

f(x,t)=1/(1-p(x,1)*t +t^m): m the depth of the recursion.

as a recursion of the form:

p(x,n)=p(x,1)*p(x,n-1)-p(x,n-m).

Links

Table of n, a(n) for n=1..66.

Formula

f(x,t)=1/(1 - 2*x*t + t^4); f(x,t)=Sum[q(x,n)*t^n,{n,1,Infinity}]; p(x,-1)=0;p(x,0)=1;p(x,1)=2*x;p(x,2)=4*x^2; p(x, n) = 2*x*p(x, n - 1) - p(x, n - 4);

Mathematica

(*expansion polynomial*) Clear[p, a] p[t_] = 1/(1 - 2*x*t + t^4) g = Table[ ExpandAll[SeriesCoefficient[ Series[p[t], {t, 0, 30}], n]], {n, 0, 10}]; a = Table[ CoefficientList[SeriesCoefficient[ Series[p[t], {t, 0, 30}], n], x], {n, 0, 10}]; Flatten[a] (* recursion polynomial*) Clear[p] p[x, -1]=0; p[x, 0] = 1; p[x, 1] = 2x; p[x, 2] = 4x^2; p[x_, n_] := p[x, n] = 2*x*p[x, n - 1] - p[x, n - 4]; Table[ExpandAll[p[x, n]], {n, 0, Length[g] - 1}]; Flatten[Table[CoefficientList[p[x, n], x], {n, 0, Length[g] - 1}]]

Crossrefs

Cf. A008937.

Sequence in context: A321256 A130123 A319935 * A028601 A077958 A077959

Adjacent sequences: A136334 A136335 A136336 * A136338 A136339 A136340

Keyword

tabl,uned,sign

Author

Roger L. Bagula, Apr 12 2008

Status

approved