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.

A330432 Number of permutations sigma of [n] such that k * sigma(k) >= n for 1 <= k <= n.

Table of values

n a(n)
0 1
1 1
2 1
3 1
4 2
5 4
6 18
7 54
8 384
9 1920
10 15000
11 108000
12 1270080
13 8890560
14 126443520
15 1440270720
16 18811699200
17 232243200000
18 4303470124800
19 56336336179200
20 1165698293760000
21 17784994106880000
22 349410939842764800
23 6977881195084800000
24 173541988447027200000

List of values

[1, 1, 1, 1, 2, 4, 18, 54, 384, 1920, 15000, 108000, 1270080, 8890560, 126443520, 1440270720, 18811699200, 232243200000, 4303470124800, 56336336179200, 1165698293760000, 17784994106880000, 349410939842764800, 6977881195084800000, 173541988447027200000]

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

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