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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A260325 Triangle read by rows: T(n,k) = logarithmic polynomial A_k^(n)(x) evaluated at x=-1.

Original entry on oeis.org

1, 2, 1, 5, 2, 2, 16, 9, 6, 6, 65, 28, 12, 24, 24, 326, 185, 140, 60, 120, 120, 1957, 846, 750, 120, 360, 720, 720, 13700, 7777, 2562, 5250, 840, 2520, 5040, 5040, 109601, 47384, 47096, 40656, 1680, 6720, 20160, 40320, 40320, 986410, 559953, 378072, 181944, 365904, 15120, 60480, 181440, 362880, 362880
Offset: 1

Views

Author

N. J. A. Sloane, Jul 23 2015

Keywords

Examples

			Triangle begins:
     1;
     2,   1;
     5,   2,   2;
    16,   9,   6,   6;
    65,  28,  12,  24,  24;
   326, 185, 140,  60, 120, 120;
  1957, 846, 750, 120, 360, 720, 720;
  ...
		

Crossrefs

Rows, column sums give A000522, A002747, A002750, A002751.
Main diagonal gives A000142.

Programs

  • Maple
    A260325 := proc(n,r)
        if r = 0 then
            1 ;
        elif n > r+1 then
            0 ;
        else
            add( 1/(r-j*n+1)!,j=1..(r+1)/n) ;
            %*r! ;
        end if;
    end proc:
    for r from 0 to 20 do
        for n from 1 to r+1 do
            printf("%a,",A260325(n,r)) ;
        end do:
        printf("\n") ;
    end do: # R. J. Mathar, Jul 24 2015
  • Mathematica
    T[n_, k_] := Which[n == 0, 1, k > n+1, 0, True, Sum[1/(n-j*k+1)!, {j, 1, (n+1)/k}]*n!];
    Table[T[n, k], {n, 0, 9}, {k, 1, n+1}] // Flatten (* Jean-François Alcover, Apr 25 2023 *)
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