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.

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A368488 a(n) = Sum_{k=0..n} n^k * binomial(k+n-1,k).

Original entry on oeis.org

1, 2, 17, 334, 10417, 442276, 23690809, 1530206742, 115636017473, 10004657077468, 974950612575601, 105653682110368492, 12602144701834193521, 1640558582759557298696, 231448351542446473323113, 35173958220088874039434726, 5728588740444710703061240065
Offset: 0

Views

Author

Seiichi Manyama, Dec 26 2023

Keywords

Crossrefs

Main diagonal of A368487.

Programs

  • PARI
    a(n) = sum(k=0, n, n^k*binomial(k+n-1, k));

Formula

a(n) = [x^n] 1/((1-x) * (1-n*x)^n).
a(n) ~ 2^(2*n-1) * n^(n - 1/2) / sqrt(Pi). - Vaclav Kotesovec, Dec 27 2023

A368506 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{j=0..n} k^(n-j) * binomial(j+k-1,j).

Original entry on oeis.org

1, 1, 0, 1, 2, 0, 1, 4, 3, 0, 1, 6, 11, 4, 0, 1, 8, 24, 26, 5, 0, 1, 10, 42, 82, 57, 6, 0, 1, 12, 65, 188, 261, 120, 7, 0, 1, 14, 93, 360, 787, 804, 247, 8, 0, 1, 16, 126, 614, 1870, 3204, 2440, 502, 9, 0, 1, 18, 164, 966, 3810, 9476, 12900, 7356, 1013, 10, 0
Offset: 0

Views

Author

Seiichi Manyama, Dec 27 2023

Keywords

Examples

			Square array begins:
  1, 1,   1,    1,     1,     1,      1, ...
  0, 2,   4,    6,     8,    10,     12, ...
  0, 3,  11,   24,    42,    65,     93, ...
  0, 4,  26,   82,   188,   360,    614, ...
  0, 5,  57,  261,   787,  1870,   3810, ...
  0, 6, 120,  804,  3204,  9476,  23112, ...
  0, 7, 247, 2440, 12900, 47590, 139134, ...
		

Crossrefs

Columns k=0..3 give A000007, A000027(n+1), A125128(n+1), A052150.
Main diagonal gives A293574.

Programs

  • PARI
    T(n, k) = sum(j=0, n, k^(n-j)*binomial(j+k-1, j));

Formula

G.f. of column k: 1/((1-k*x) * (1-x)^k).
Showing 1-2 of 2 results.