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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A177286 Number of permutations of 2 copies of 1..n with all adjacent differences <= 5 in absolute value.

Original entry on oeis.org

1, 1, 6, 90, 2520, 113400, 7484400, 349272000, 12629539440, 394462558980, 11673071453460, 348672825749478, 10924880404749722, 348078897908489130, 11059657083803795688, 346844915294462956440, 10705742604901078977600
Offset: 0

Views

Author

R. H. Hardin, May 06 2010

Keywords

Comments

a(n) = (2n)!/2^n for n<=6.

Crossrefs

Cf. A177282, A177283, A177284, A177285, A177287, A177288, A177289, A177290, A177295.

Extensions

a(0)=1 and a(12)-a(16) from Max Alekseyev, May 30 2025
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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