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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A294046 Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f.: exp(1/(1-x)^k - 1).

Original entry on oeis.org

1, 1, 0, 1, 1, 0, 1, 2, 3, 0, 1, 3, 10, 13, 0, 1, 4, 21, 68, 73, 0, 1, 5, 36, 195, 580, 501, 0, 1, 6, 55, 424, 2241, 5912, 4051, 0, 1, 7, 78, 785, 6136, 30483, 69784, 37633, 0, 1, 8, 105, 1308, 13705, 104544, 476469, 933200, 394353, 0, 1, 9, 136, 2023, 26748
Offset: 0

Views

Author

Seiichi Manyama, Oct 22 2017

Keywords

Examples

			Square array A(n,k) begins:
   1,   1,    1,     1,      1, ...
   0,   1,    2,     3,      4, ...
   0,   3,   10,    21,     36, ...
   0,  13,   68,   195,    424, ...
   0,  73,  580,  2241,   6136, ...
   0, 501, 5912, 30483, 104544, ...
		

Crossrefs

Columns k=0..5 give A000007, A000262, A136658, A202826, A294050, A294051.
Rows n=0..2 give A000012, A001477, A014105.
Main diagonal gives A294047.
Cf. A291709.

Programs

  • Mathematica
    A[0, ] = 1; A[n, k_] := k*(n-1)!*Sum[Binomial[j+k-1, k]*A[n-j, k]/(n-j)!, {j, 1, n}];
    Table[A[n-k, k], {n, 0, 10}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Nov 03 2017 *)

Formula

A(0,k) = 1 and A(n,k) = k * (n-1)! * Sum_{j=1..n} binomial(j+k-1,k)*A(n-j,k)/(n-j)! for n > 0.

A294192 a(n) = n! * [x^n] exp(n*(1/(1-x)^n- 1)).

Original entry on oeis.org

1, 1, 28, 1881, 241696, 50903725, 15950981376, 6965675824177, 4044321664205824, 3013398202413705561, 2802908316869098624000, 3183461016834811739809321, 4335741846110695855971852288, 6974958097518147761490109983781
Offset: 0

Views

Author

Seiichi Manyama, Oct 24 2017

Keywords

Crossrefs

Main diagonal of A294188.
Cf. A294047.

Programs

  • Maple
    S:= series(exp(n*(1/(1-x)^n-1)),x,31):
    seq(n!*coeff(S,x,n),n=0..30); # Robert Israel, Oct 24 2017
  • Mathematica
    Table[n! SeriesCoefficient[Exp[n (1 / (1 - x)^n - 1)], {x, 0, n}], {n, 0, 20}] (* Vincenzo Librandi, Oct 25 2017 *)
Showing 1-2 of 2 results.