cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A171693 Expansion of g.f.: 2^(1+floor(n/2))*n!*((1-y)^(n+1)/(1+y))*f(x, y, m), where f(x, y, m) = 2^(m+1)*exp(2^m*t)/((1-y*exp(t))*(1 + (2^(m+1)-1)*exp(2^m*t))), and m = 0.

Original entry on oeis.org

1, -1, 14, -1, 4, -16, 504, -16, 4, -34, 372, 2178, 35288, 2178, 372, -34, 496, -5888, 65728, 749824, 4185760, 749824, 65728, -5888, 496, -11056, 154912, -767856, 23350656, 230640288, 770603712, 230640288, 23350656, -767856, 154912, -11056
Offset: 0

Views

Author

Roger L. Bagula, Dec 15 2009

Keywords

Examples

			Irregular triangle begins as:
    1;
   -1,    14,    -1;
    4,   -16,   504,    -16,       4;
  -34,   372,  2178,  35288,    2178,    372,   -34;
  496, -5888, 65728, 749824, 4185760, 749824, 65728, -5888, 496;
		

Crossrefs

Programs

  • Mathematica
    m= 0;
    f[t_, y_, m_]= 2^(m+1)*Exp[2^m*t]/((1-y*Exp[t])*(1+(2^(m+1)-1)*Exp[2^m*t]));
    T[n_]:= T[n]= CoefficientList[2^(1+Floor[n/2])*n!*(1-y)^(n+1)/(1 + y)*SeriesCoefficient[Series[f[t, y, m], {t,0,20}], n], y];
    Table[T[2*n+1], {n,0,12}]//Flatten (* modified by G. C. Greubel, Mar 30 2022 *)

Formula

G.f.: 2^(1+floor(n/2))*n!*((1-y)^(n+1)/(1+y))*f(x, y, m), where f(x, y, m) = 2^(m+1)*exp(2^m*t)/((1-y*exp(t))*(1 + (2^(m+1)-1)*exp(2^m*t))), and m = 0.

Extensions

Edited by G. C. Greubel, Mar 31 2022