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.

Showing 1-3 of 3 results.

A344640 Antidiagonal sums of A344639.

Original entry on oeis.org

1, 2, 5, 16, 63, 297, 1649, 10641, 78823, 662315, 6241889, 65294039, 751035233, 9420926879, 127958645921, 1870319380463, 29263787708393, 487891616911031, 8632986776222945, 161555987833199807, 3187606376603319017, 66128414623822131863, 1438861202348688524897, 32763278185929878499887
Offset: 0

Views

Author

Stefano Spezia, May 25 2021

Keywords

Crossrefs

Programs

  • Mathematica
    Table[Sum[Sum[Abs[StirlingS1[n-k,m]](m+1)^k,{m,0,n-k}],{k,0,n}],{n,0,23}]

Formula

a(n) = Sum_{k=0..n} Sum_{m=0..n-k} abs(S1(n-k, m))*(m + 1)^k, where S1 indicates the signed Stirling numbers of first kind.
Conjecture: a(n) ~ n!. - Vaclav Kotesovec, May 26 2021

A192563 a(n) = Sum_{k=0..n} abs(Stirling1(n+1,k+1))*Stirling2(n+1,k+1)*k!.

Original entry on oeis.org

1, 2, 13, 161, 3148, 87784, 3274640, 156359874, 9252910816, 662065322016, 56172251821992, 5562573507747288, 634574662217269824, 82482896750780978880, 12101565966159294983808, 1987899464090970683668944, 363036441677797499946379776
Offset: 0

Views

Author

Emanuele Munarini, Jul 04 2011

Keywords

Crossrefs

Diagonal of the array A344639.

Programs

  • Mathematica
    Table[Sum[Abs[StirlingS1[n+1,k+1]]StirlingS2[n+1,k+1]k!,{k,0,n}],{n,0,100}]
  • Maxima
    makelist(sum(abs(stirling1(n+1,k+1))*stirling2(n+1,k+1)*k!,k,0,n),n,0,12);

A383064 Square array A(n,k), n>=0, k>=0, read by antidiagonals downwards, where column k is the expansion of e.g.f. Sum_{j>=0} (j+1)^k * (-log(1-x))^j / j!.

Original entry on oeis.org

1, 1, 1, 1, 2, 2, 1, 4, 5, 6, 1, 8, 13, 17, 24, 1, 16, 35, 51, 74, 120, 1, 32, 97, 161, 244, 394, 720, 1, 64, 275, 531, 854, 1392, 2484, 5040, 1, 128, 793, 1817, 3148, 5248, 9260, 18108, 40320, 1, 256, 2315, 6411, 12134, 20940, 36966, 70508, 149904, 362880
Offset: 0

Views

Author

Seiichi Manyama, Apr 15 2025

Keywords

Examples

			Square array begins:
    1,    1,    1,     1,      1,      1,       1, ...
    1,    2,    4,     8,     16,     32,      64, ...
    2,    5,   13,    35,     97,    275,     793, ...
    6,   17,   51,   161,    531,   1817,    6411, ...
   24,   74,  244,   854,   3148,  12134,   48604, ...
  120,  394, 1392,  5248,  20940,  87784,  384252, ...
  720, 2484, 9260, 36966, 156680, 699894, 3274640, ...
		

Crossrefs

Mirror of A344639.
Main diagonal gives A192563.

Programs

  • PARI
    a(n, k) = sum(j=0, n, j!*abs(stirling(n+1, j+1, 1))*stirling(k+1, j+1, 2));

Formula

See A344639.
Showing 1-3 of 3 results.