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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A369738 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals, where column k is the expansion of e.g.f. exp(1 - (1+x)^k).

Original entry on oeis.org

1, 1, 0, 1, -1, 0, 1, -2, 1, 0, 1, -3, 2, -1, 0, 1, -4, 3, 4, 1, 0, 1, -5, 4, 21, -20, -1, 0, 1, -6, 5, 56, -63, 8, 1, 0, 1, -7, 6, 115, -104, -423, 184, -1, 0, 1, -8, 7, 204, -95, -2464, 1899, -464, 1, 0, 1, -9, 8, 329, 36, -8245, 1696, 15201, -1648, -1, 0
Offset: 0

Views

Author

Seiichi Manyama, Jan 30 2024

Keywords

Examples

			Square array T(n,k) begins:
  1,  1,   1,    1,     1,      1,       1, ...
  0, -1,  -2,   -3,    -4,     -5,      -6, ...
  0,  1,   2,    3,     4,      5,       6, ...
  0, -1,   4,   21,    56,    115,     204, ...
  0,  1, -20,  -63,  -104,    -95,      36, ...
  0, -1,   8, -423, -2464,  -8245,  -21096, ...
  0,  1, 184, 1899,  1696, -21275, -124344, ...
		

Crossrefs

Columns k=0..5 give A000007, A033999, (-1)^n * A062267(n), A369751, A369752, A369753.
Main diagonal gives A369754.

Programs

  • PARI
    a000587(n) = sum(k=0, n, (-1)^k*stirling(n, k, 2));
    T(n, k) = sum(j=0, n, k^j*stirling(n, j, 1)*a000587(j));

Formula

T(0,k) = 1; T(n,k) = -k * (n-1)! * Sum_{j=1..min(k,n)} binomial(k-1,j-1) * T(n-j,k)/(n-j)!.
T(n,k) = Sum_{j=0..n} k^j * Stirling1(n,j) * A000587(j).

A369756 Expansion of e.g.f. exp( (1 - (1+x)^5)/5 ).

Original entry on oeis.org

1, -1, -3, -1, 49, 255, -275, -13105, -83775, 170495, 8290045, 69257055, -111005135, -9684015745, -109196883795, -31470300625, 17728458119425, 276531029694975, 904537471692925, -44728487203650625, -1000823562359108175, -7110596979389965825
Offset: 0

Views

Author

Seiichi Manyama, Jan 31 2024

Keywords

Crossrefs

Programs

  • PARI
    my(N=30, x='x+O('x^N)); Vec(serlaplace(exp((1-(1+x)^5)/5)))

Formula

a(0) = 1; a(n) = -(n-1)! * Sum_{k=1..min(5,n)} binomial(4,k-1) * a(n-k)/(n-k)!.
a(n) = Sum_{k=0..n} 5^k * Stirling1(n,k) * Bell_k(-1/5), where Bell_n(x) is n-th Bell polynomial.
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