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.

A178346 Triangle read by rows: T(n, k, m) = binomial(n, k) - m*binomial(n, k)*binomial(n+1, k)/(k+1) + m*A008292(n+1, k+1) with m = 3.

Original entry on oeis.org

1, 1, 1, 1, 5, 1, 1, 18, 18, 1, 1, 52, 144, 52, 1, 1, 131, 766, 766, 131, 1, 1, 303, 3273, 6743, 3273, 303, 1, 1, 664, 12312, 45422, 45422, 12312, 664, 1, 1, 1406, 42844, 261230, 463348, 261230, 42844, 1406, 1, 1, 2913, 141936, 1358100, 3915312, 3915312, 1358100, 141936, 2913, 1, 1, 5953, 455481, 6595734, 29172972, 47114784, 29172972, 6595734, 455481, 5953, 1
Offset: 0

Views

Author

Roger L. Bagula, May 25 2010

Keywords

Examples

			Triangle begins as:
  1;
  1,    1;
  1,    5,      1;
  1,   18,     18,       1;
  1,   52,    144,      52,       1;
  1,  131,    766,     766,     131,       1;
  1,  303,   3273,    6743,    3273,     303,       1;
  1,  664,  12312,   45422,   45422,   12312,     664,      1;
  1, 1406,  42844,  261230,  463348,  261230,   42844,   1406,    1;
  1, 2913, 141936, 1358100, 3915312, 3915312, 1358100, 141936, 2913,   1;
		

Crossrefs

Cf. A008292.

Programs

  • Magma
    A178346:= func< n,k | Binomial(n, k) - 3*(Binomial(n, k)*Binomial(n+1, k)/(k+1)) + 3*EulerianNumber(n+1, k) >;
    [A178346(n,k): k in [0..n], n in [0..15]]; // G. C. Greubel, Oct 05 2024
    
  • Mathematica
    EulerianNumber[n_, k_] := EulerianNumber[n, k] = Sum[(-1)^j*(k-j)^n*Binomial[n+ 1, j], {j,0,k}];
    A178346[n_, k_, m_]:= Binomial[n, k] - m*Binomial[n, k]*Binomial[n+1, k]/(k+1) + m*EulerianNumber[n+1, k+1];
    Table[A178346[n,k,3], {n,0,15}, {k,0,n}]//Flatten
  • SageMath
    def A008292(n,k): return sum((-1)^j*binomial(n+1, j)*(k-j)^n for j in (0..k))
    def A178346(n,k): return binomial(n,k) - 3*binomial(n,k)*binomial(n+1,k)/(k+1) + 3*A008292(n+1,k+1)
    flatten([[A178346(n,k) for k in range(n+1)] for n in range(16)]) # G. C. Greubel, Oct 05 2024

Formula

T(n, k, m) = binomial(n, k) - m*binomial(n, k)*binomial(n+1, k)/(k+1) + m*Eulerian(n+1, k+1) with m = 3, and Eulerian(n,k) = A008292(n,k).
Sum_{k=0..n} T(n, k) = 2^n + 3*(n+1)! - 3*Catalan(n+1) = 2^n + 3*A056986(n+1). - G. C. Greubel, Oct 05 2024

Extensions

Edited by G. C. Greubel, Oct 05 2024