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.

A152495 1/3 of the number of permutations of 2 indistinguishable copies of 1..n with exactly 3 local maxima.

Table of values

n a(n)
1 0
2 0
3 8
4 483
5 16205
6 430078
7 10210206
8 228926441
9 4979392831
10 106552681812
11 2260112122016
12 47713890438655
13 1004771692065345
14 21130651257100970
15 444074589574292578
16 9329140064903065365
17 195950323696361689667
18 4115367075816142112512
19 86427075922333935342372

List of values

[0, 0, 8, 483, 16205, 430078, 10210206, 228926441, 4979392831, 106552681812, 2260112122016, 47713890438655, 1004771692065345, 21130651257100970, 444074589574292578, 9329140064903065365, 195950323696361689667, 4115367075816142112512, 86427075922333935342372]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.