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.

A156581 Triangle T(n, k, m) = (m+2)^(k*(n-k)) with m = 15, read by rows.

Original entry on oeis.org

1, 1, 1, 1, 17, 1, 1, 289, 289, 1, 1, 4913, 83521, 4913, 1, 1, 83521, 24137569, 24137569, 83521, 1, 1, 1419857, 6975757441, 118587876497, 6975757441, 1419857, 1, 1, 24137569, 2015993900449, 582622237229761, 582622237229761, 2015993900449, 24137569, 1
Offset: 0

Views

Author

Roger L. Bagula, Feb 10 2009

Keywords

Examples

			Triangle begins as:
  1;
  1,       1;
  1,      17,          1;
  1,     289,        289,            1;
  1,    4913,      83521,         4913,          1;
  1,   83521,   24137569,     24137569,      83521,       1;
  1, 1419857, 6975757441, 118587876497, 6975757441, 1419857, 1;
		

Crossrefs

Cf. A117401 (m=0), A118180 (m=1), A118185 (m=2), A118190 (m=3), A158116 (m=4), A176642 (m=6), A158117 (m=8), A176627 (m=10), A176639 (m=13), this sequence (m=15).

Programs

  • Magma
    A156581:= func< n,k,m | (m+2)^(k*(n-k)) >;
    [A156581(n,k,15): k in [0..n], n in [0..12]]; // G. C. Greubel, Jun 28 2021
    
  • Mathematica
    (* First program *)
    b[n_, k_]:= b[n, k]= If[k==0, n!, Product[Sum[Binomial[j-1, i]*(k+1)^i, {i, 0, j-1}], {j, n}]];
    T[n_, k_, m_]:= T[n, k, m]= b[n, m]/(b[k, m]*b[n-k, m]);
    Table[T[n, k, 15], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jun 28 2021 *)
    (* Second program *)
    T[n_, k_, m_]:= (m+2)^(k*(n-k)); Table[T[n,k,15], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Jun 28 2021 *)
  • Sage
    def A156581(n,k,m): return (m+2)^(k*(n-k))
    flatten([[A156581(n,k,15) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jun 28 2021

Formula

T(n, k, m) = b(n, m)/(b(k, m)*b(n-k, m)) with b(n, k) = Product_{j=1..n} ( Sum_{i=0..j-1} binomial(j-1, i)*(k+1)^i ), b(n, 0) = n!, and m = 15.
T(n, k, m) = (m+2)^(k*(n-k)) with m = 15. - G. C. Greubel, Jun 28 2021

Extensions

Edited by G. C. Greubel, Jun 28 2021