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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A374738 Table read by ascending antidiagonals: T(m,n) = number of (n-1)-metered (m,n)-parking functions.

Original entry on oeis.org

1, 1, 2, 1, 3, 3, 1, 4, 8, 4, 1, 6, 16, 15, 5, 1, 8, 27, 50, 24, 6, 1, 12, 48, 125, 108, 35, 7, 1, 16, 96, 257, 432, 196, 48, 8, 1, 24, 162, 540, 1296, 1029, 320, 63, 9, 1, 32, 288, 1200, 3156, 4802, 2048, 486, 80, 10, 1, 48, 576, 3000, 7734, 16807, 12288, 3645, 700, 99, 11
Offset: 1

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Author

Spencer Daugherty, Jul 18 2024

Keywords

Examples

			Table begins:
   1,  2,   3,    4,    5,     6,      7, ...
   1,  3,   8,   15,   24,    35,     48, ...
   1,  4,  16,   50,  108,   196,    320, ...
   1,  6,  27,  125,  432,  1029,   2048, ...
   1,  8,  48,  257, 1296,  4802,  12288, ...
   1, 12,  96,  540, 3156, 16807,  65536, ...
   1, 16, 162, 1200, 7734, 47442, 262144, ...
   ...
		

Crossrefs

The n=m+1 diagonal is A007334.

Formula

T(n+k,n) = Sum_{sigma = (sigma_1, ..., sigma_n) in S_n} (( Product_{i=1..n} L_{i}(sigma))( Product_{j=1..k} sigma_j mod n )), where k>0 and L_{i}(sigma) is the largest index h with i= sigma_N for all N in {i-j, i-j+1, ..., i-1, i}.

A375902 E.g.f. satisfies A(x) = (2 - exp(x * A(x)^(1/2)))^2.

Original entry on oeis.org

1, -2, 4, -2, -52, 358, 12, -25986, 247228, 821398, -52933300, 534428926, 6201248220, -271179578490, 2375560802188, 75726973445374, -2740636867741828, 14280527041851958, 1501820173046702796, -46939564687781824002, -67963035486950641508
Offset: 0

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Author

Seiichi Manyama, Sep 02 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace((serreverse(x/(2-exp(x)))/x)^2))
    
  • PARI
    a(n) = 2*(n+1)!*sum(k=0, n, (-1)^k*stirling(n, k, 2)/(n-k+2)!);

Formula

E.g.f.: A(x) = ( (1/x) * Series_Reversion(x / (2 - exp(x))) )^2.
a(n) = 2 * (n+1)! * Sum_{k=0..n} (-1)^k * Stirling2(n,k)/(n-k+2)!.
Previous Showing 11-12 of 12 results.