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.

A104986 Matrix logarithm of triangle A104980.

Original entry on oeis.org

0, 1, 0, 2, 2, 0, 7, 4, 3, 0, 33, 14, 7, 4, 0, 191, 66, 27, 11, 5, 0, 1297, 382, 137, 48, 16, 6, 0, 10063, 2594, 843, 270, 79, 22, 7, 0, 87669, 20126, 6041, 1820, 495, 122, 29, 8, 0, 847015, 175338, 49219, 14176, 3679, 848, 179, 37, 9, 0, 8989301, 1694030, 448681, 124828, 31361, 6930, 1371, 252, 46, 10, 0
Offset: 0

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Author

Paul D. Hanna, Apr 10 2005

Keywords

Comments

Column 0 equals column 1 of triangular matrix A104980, which satisfies: SHIFT_LEFT(column 0 of A104980^p) = p*(column p+1 of A104980) for p>=0. Column 1 equals twice column 0.

Examples

			Triangle begins:
        0;
        1,       0;
        2,       2,      0;
        7,       4,      3,      0;
       33,      14,      7,      4,     0;
      191,      66,     27,     11,     5,    0;
     1297,     382,    137,     48,    16,    6,    0;
    10063,    2594,    843,    270,    79,   22,    7,   0;
    87669,   20126,   6041,   1820,   495,  122,   29,   8,  0;
   847015,  175338,  49219,  14176,  3679,  848,  179,  37,  9,  0;
  8989301, 1694030, 448681, 124828, 31361, 6930, 1371, 252, 46, 10, 0; ...
		

Crossrefs

Cf. A104980, A104981 (column 0), A104987 (row sums).

Programs

  • Mathematica
    nmax = 10;
    M = Table[If[n == k, 0, If[n == k+1, -n+1, -Coefficient[(1-1/Sum[i! x^i, {i, 0, n}])/x + O[x]^n, x, n-k-1]]], {n, 1, nmax+1}, {k, 1, nmax+1}];
    T[n_, k_] /; 0 <= k <= n := Sum[(-1)^p MatrixPower[M, p][[n+1, k+1]]/p, {p, 1, n+1}]; T[, ] = 0;
    Table[T[n, k], {n, 0, nmax}, {k, 0, n}] // Flatten (* Jean-François Alcover, Aug 09 2018, from PARI *)
  • PARI
    T(n,k)=if(n
    				

Formula

T(n, 0) = A104981(n), T(n+1, 1) = 2*T(n, 0) for n>=0.