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.

A154647 Triangle, T(n, k) = [x^k]( p(x, n) ), where (1/2)*(1-x)^(n+1) * Sum_{j >= 0} ((4*j + 3)^n + (4*j+1)^n )*x^j, read by rows.

Original entry on oeis.org

1, 2, 2, 5, 22, 5, 14, 178, 178, 14, 41, 1308, 3446, 1308, 41, 122, 9234, 52084, 52084, 9234, 122, 365, 64082, 692707, 1434812, 692707, 64082, 365, 1094, 442082, 8559030, 32285474, 32285474, 8559030, 442082, 1094, 3281, 3048184, 101121500, 641507528, 1151050534, 641507528, 101121500, 3048184, 3281
Offset: 0

Views

Author

Roger L. Bagula, Jan 13 2009

Keywords

Examples

			Triangle begins as:
     1;
     2,      2;
     5,     22,       5;
    14,    178,     178,       14;
    41,   1308,    3446,     1308,       41;
   122,   9234,   52084,    52084,     9234,     122;
   365,  64082,  692707,  1434812,   692707,   64082,    365;
  1094, 442082, 8559030, 32285474, 32285474, 8559030, 442082, 1094;
		

Crossrefs

Cf. A007051, A047053 (row sums), A154646.

Programs

  • Magma
    m:=12;
    R:=PowerSeriesRing(Integers(), m+2);
    p:= func< n,x | (1-x)^(n+1)*(&+[((4*j+3)^n+(4*j+1)^n)/2*x^j: j in [0..m+2]]) >;
    T:= func< n,k | Coefficient(R!( p(n,x) ), k) >;
    [T(n,k): k in [0..n], n in [0..m]]; // G. C. Greubel, May 27 2024
    
  • Mathematica
    m=12; p[x_, n_]= (1/2)*(1-x)^(n+1)*Sum[((4*j+3)^n + (4*j+1)^n)*x^j, {j,0,m +2}]; T[n_, k_]:= Coefficient[p[x, n], x, k];
    Table[T[n,k], {n,0,m}, {k,0,n}]//Flatten
  • SageMath
    m=12
    def p(x,n): return (1-x)^(n+1)*sum( ((4*j+3)^n +(4*j+1)^n)*x^j for j in range(m+2))/2
    def T(n,k): return ( p(x,n) ).series(x, n+1).list()[k]
    flatten([[T(n,k) for k in range(n+1)] for n in range(m+1)]) # G. C. Greubel, May 27 2024

Formula

T(n, k) = [x^k]( p(x, n) ), where (1/2)*(1-x)^(n+1) * Sum_{j >= 0} ((4*j + 3)^n + (4*j+1)^n )*x^j.
T(n, n-k) = T(n, k).
Sum_{k=0..n} T(n, k) = A047053(n) (row sums).
T(n, 0) = T(n, n) = A007051(n). - G. C. Greubel, May 27 2024

Extensions

Edited by G. C. Greubel, May 27 2024