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.

A277031 Number T(n,k) of permutations of [n] where the minimal cyclic distance between elements of the same cycle equals k (k=n for the identity permutation in S_n); triangle T(n,k), n>=0, 0<=k<=n, read by rows.

Original entry on oeis.org

1, 0, 1, 0, 1, 1, 0, 5, 0, 1, 0, 20, 3, 0, 1, 0, 109, 10, 0, 0, 1, 0, 668, 44, 7, 0, 0, 1, 0, 4801, 210, 28, 0, 0, 0, 1, 0, 38894, 1320, 90, 15, 0, 0, 0, 1, 0, 353811, 8439, 554, 75, 0, 0, 0, 0, 1, 0, 3561512, 63404, 3542, 310, 31, 0, 0, 0, 0, 1, 0, 39374609, 517418, 23298, 1276, 198, 0, 0, 0, 0, 0, 1
Offset: 0

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Author

Alois P. Heinz, Sep 25 2016

Keywords

Examples

			T(3,1) = 5: (1,2,3), (1,3,2), (1)(2,3), (1,2)(3), (1,3)(2).
T(3,3) = 1: (1)(2)(3).
Triangle T(n,k) begins:
  1;
  0,       1;
  0,       1,     1;
  0,       5,     0,    1;
  0,      20,     3,    0,   1;
  0,     109,    10,    0,   0,  1;
  0,     668,    44,    7,   0,  0, 1;
  0,    4801,   210,   28,   0,  0, 0, 1;
  0,   38894,  1320,   90,  15,  0, 0, 0, 1;
  0,  353811,  8439,  554,  75,  0, 0, 0, 0, 1;
  0, 3561512, 63404, 3542, 310, 31, 0, 0, 0, 0, 1;
  ...
		

Crossrefs

Columns k=0-1 give: A000007, A277032.
Row sums give A000142.
T(2n,n) = A255047(n) = A000225(n) for n>0.