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.

A156788 Triangle T(n, k) = binomial(n, k)*A000166(n-k)*k^n with T(0, 0) = 1, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 0, 4, 0, 3, 0, 27, 0, 8, 96, 0, 256, 0, 45, 640, 2430, 0, 3125, 0, 264, 8640, 29160, 61440, 0, 46656, 0, 1855, 118272, 688905, 1146880, 1640625, 0, 823543, 0, 14832, 1899520, 16166304, 41287680, 43750000, 47029248, 0, 16777216, 0, 133497, 34172928, 438143580, 1453326336, 2214843750, 1693052928, 1452729852, 0, 387420489
Offset: 0

Views

Author

Roger L. Bagula, Feb 15 2009

Keywords

Examples

			Triangle begins as:
  1;
  0,     1;
  0,     0,       4;
  0,     3,       0,       27;
  0,     8,      96,        0,      256;
  0,    45,     640,     2430,        0,     3125;
  0,   264,    8640,    29160,    61440,        0,    46656;
  0,  1855,  118272,   688905,  1146880,  1640625,        0, 823543;
  0, 14832, 1899520, 16166304, 41287680, 43750000, 47029248,      0, 16777216;
		

References

  • J. Riordan, Combinatorial Identities, Wiley, 1968, p.194.

Crossrefs

Programs

  • Mathematica
    A000166[n_]:= A000166[n]= If[n==0, 1, n*A000166[n-1] + (-1)^n];
    T[n_, k_]:= If[n==0, 1, Binomial[n, k]*A000166[n-k]*k^n];
    Table[T[n, k], {n,0,12}, {k,0,n}]//Flatten (* modified by G. C. Greubel, Jun 10 2021 *)
  • Sage
    def A000166(n): return 1 if (n==0) else n*A000166(n-1) + (-1)^n
    def A156788(n,k): return 1 if (n==0) else binomial(n,k)*k^n*A000166(n-k)
    flatten([[A156788(n,k) for k in (0..n)] for n in (0..12)]) # G. C. Greubel, Jun 10 2021

Formula

T(n, k) = binomial(n, k)*A000166(n-k)*k^n with T(0, 0) = 1.
T(n, k) = binomial(n, k)*b(n-k)*k^n, where b(n) = n*b(n-1) + (-1)^n and b(0) = 1.
Sum_{k=0..n} T(n, k) = A137341(n).
From G. C. Greubel, Jun 10 2021: (Start)
T(n, 1) = A000240(n).
T(n, n) = A000312(n). (End)

Extensions

Edited by G. C. Greubel, Jun 10 2021