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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A362588 Triangle read by rows, T(n, k) = RisingFactorial(n - k, k) * FallingFactorial(n, k).

Original entry on oeis.org

1, 1, 0, 1, 2, 0, 1, 6, 12, 0, 1, 12, 72, 144, 0, 1, 20, 240, 1440, 2880, 0, 1, 30, 600, 7200, 43200, 86400, 0, 1, 42, 1260, 25200, 302400, 1814400, 3628800, 0, 1, 56, 2352, 70560, 1411200, 16934400, 101606400, 203212800, 0
Offset: 0

Views

Author

Peter Luschny, May 05 2023

Keywords

Examples

			Table T(n, k) begins:
[0] 1;
[1] 1,  0;
[2] 1,  2,    0;
[3] 1,  6,   12,     0;
[4] 1, 12,   72,   144,       0;
[5] 1, 20,  240,  1440,    2880,        0;
[6] 1, 30,  600,  7200,   43200,    86400,         0;
[7] 1, 42, 1260, 25200,  302400,  1814400,   3628800,         0;
[8] 1, 56, 2352, 70560, 1411200, 16934400, 101606400, 203212800, 0;
		

Crossrefs

Cf. A228229 (row sums), A002378 (column 1), A010790 (subdiagonal).

Programs

  • Maple
    T := (n, k) -> (-1)^k*pochhammer(n - k, k)*pochhammer(-n, k):
    for n from 0 to 6 do seq(T(n, k), k=0..n) od;

Formula

T(n, k) = (-1)^k * Pochhammer(n - k, k) * Pochhammer(-n, k).
T(n, k) = binomial(n, k) * binomial(n - 1, k) * (k!)^2.

A368787 a(n) = (n+1) * (n!)^2 * Sum_{k=1..n} 1/((k+1) * (k!)^2).

Original entry on oeis.org

0, 1, 7, 85, 1701, 51031, 2143303, 120024969, 8641797769, 777761799211, 85553797913211, 11293101324543853, 1761723806628841069, 320633732806449074559, 67333083889354305657391, 16159940133445033357773841, 4395503716297049073314484753
Offset: 0

Views

Author

Seiichi Manyama, Jan 05 2024

Keywords

Crossrefs

Programs

  • PARI
    a(n) = (n+1)*n!^2*sum(k=1, n, 1/((k+1)*k!^2));

Formula

a(0) = 0; a(n) = (n+1) * n * a(n-1) + 1.
a(n) = A228229(n) - (n+1) * (n!)^2.
Previous Showing 11-12 of 12 results.