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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.

A335848 a(0) = 1; a(n) = Sum_{k=1..n} binomial(n,k) * k!! * a(n-k).

Table of values

n a(n)
0 1
1 1
2 4
3 21
4 152
5 1355
6 14568
7 182427
8 2612224
9 42073209
10 752981280
11 14823367845
12 318347145216
13 7406554353939
14 185573713100160
15 4981725842622795
16 142650055922872320
17 4340032650657965745
18 139809806502181765632
19 4754045863586538697077
20 170163141506896128122880

List of values

[1, 1, 4, 21, 152, 1355, 14568, 182427, 2612224, 42073209, 752981280, 14823367845, 318347145216, 7406554353939, 185573713100160, 4981725842622795, 142650055922872320, 4340032650657965745, 139809806502181765632, 4754045863586538697077, 170163141506896128122880]

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

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