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.

A168549 Expansion of g.f. (1/2)*( a*(1+x)^n + b*(1-x)^(n+2)*LerchPhi(x, -n-1, 1) + c*2^(n+1)*(1-x)^(n+1)*LerchPhi(x, -n, 1/2) ), where a = 31, b = -59, and c = 15, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 3, 1, 1, 67, 67, 1, 1, 435, 1596, 435, 1, 1, 1951, 16476, 16476, 1951, 1, 1, 7383, 123243, 282258, 123243, 7383, 1, 1, 25507, 783537, 3435627, 3435627, 783537, 25507, 1, 1, 83595, 4543678, 34677285, 65518690, 34677285, 4543678, 83595, 1, 1, 265351, 24934378, 312192718, 1002545920, 1002545920, 312192718, 24934378, 265351, 1
Offset: 0

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Author

Roger L. Bagula, Nov 29 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,     1;
  1,     3,       1;
  1,    67,      67,        1;
  1,   435,    1596,      435,        1;
  1,  1951,   16476,    16476,     1951,        1;
  1,  7383,  123243,   282258,   123243,     7383,       1;
  1, 25507,  783537,  3435627,  3435627,   783537,   25507,     1;
  1, 83595, 4543678, 34677285, 65518690, 34677285, 4543678, 83595, 1;
		

Crossrefs

Programs

  • Mathematica
    p[x_, n_, a_, b_, c_]= (1/2)*(a*(1+x)^n + b*(1-x)^(n+2)*LerchPhi[x,-n-1,1] + c*2^(n+1)*(1-x)^(n+1)*LerchPhi[x,-n,1/2]);
    Table[CoefficientList[p[x,n,31,-59,15], x], {n,0,10}]//Flatten (* modified by G. C. Greubel, Mar 31 2022 *)
  • Sage
    def A168549(n,k,a,b,c): return (1/2)*( a*binomial(n,k) + sum( (-1)^(k-j)*(b*binomial(n+2, k-j)*(j+1)^(n+1) + 2*c*binomial(n+1,k-j)*(2*j+1)^n) for j in (0..k)) )
    flatten([[A168549(n,k,31,-59,15) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Mar 31 2022

Formula

G.f.: (1/2)*( a*(1+x)^n + b*(1-x)^(n+2)*LerchPhi(x, -n-1, 1) + c*2^(n+1)*(1 - x)^(n+1)*LerchPhi(x, -n, 1/2) ), where a = 31, b = -59, and c = 15.
From G. C. Greubel, Mar 31 2022: (Start)
T(n, k) = (1/2)*( a*binomial(n,k) + sum( (-1)^(k-j)*(b*binomial(n+2, k-j)*(j+1)^(n+1) + 2*c*binomial(n+1,k-j)*(2*j+1)^n) for j in (0..k)) ), with a = 31, b = -59, and c = 15.
T(n, n-k) = T(n, k). (End)

Extensions

Edited by G. C. Greubel, Mar 31 2022