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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A002634 From discordant permutations.

Original entry on oeis.org

-2, 3, 0, 25, 152, 1350, 12644, 131391, 1489568, 18329481, 243365514, 3468969962, 52848096274, 857073295427, 14744289690560, 268202790690465, 5143861702523924, 103746422699053582, 2195275169113687656, 48629604864202585247
Offset: 3

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Author

Keywords

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A000183.

Formula

a(n) = b(n) - 2*b(n-1) + b(n-2) + 2*a(n-1) + 2*a(n-2) - 2*a(n-3) + a(n-4) + 4*(-1)^n where b(n) = A000183(n) and n>6. a(3)=-2, a(4)=3, a(5)=0, a(6)=25. - Sean A. Irvine, May 03 2014

Extensions

More terms from Sean A. Irvine, May 03 2014

A094315 Triangle read by rows giving number of circular permutations of n letters such that all letters are displaced by no more than k places from their original position.

Original entry on oeis.org

1, 0, 1, 0, 0, 2, 0, 0, 0, 6, 1, 0, 6, 8, 9, 2, 15, 20, 40, 30, 13, 20, 72, 180, 176, 180, 72, 20, 144, 609, 1106, 1421, 980, 595, 154, 31, 1265, 4960, 9292, 10352, 8326, 4096, 1676, 304, 49
Offset: 0

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Author

N. J. A. Sloane, based on a suggestion from Anthony C Robin, Jun 02 2004

Keywords

Comments

The n-th row sums to n!.

Examples

			1;
0, 1;
0, 0, 2;
0, 0, 0, 6;
1, 0, 6, 8, 9;
2, 15, 20, 40, 30, 13;
20, 72, 180, 176, 180, 72, 20;
144, 609, 1106, 1421, 980, 595, 154, 31;
		

References

  • J. Riordan, Discordant permutations, Scripta Math., 20 (1954), 14-23.

Crossrefs

Diagonals give A000183 (which has further references), A000476, A000388, A000380, A000440, etc.
See also A061702.

Formula

Riordan (1954) is devoted to the study of these numbers and gives generating functions (involving the numbers in A061702 as coefficients).
Previous Showing 11-12 of 12 results.