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.

A356029 a(n) = n! * Sum_{k=0..floor(n/2)} (n - 2*k)^k/(2^k * (n - 2*k)!).

Table of values

n a(n)
0 1
1 1
2 1
3 4
4 13
5 61
6 421
7 2626
8 27049
9 245953
10 3069721
11 40222216
12 576988501
13 10058716669
14 169773404893
15 3596206855606
16 73450508303761
17 1775382487932001
18 43993288886533489
19 1183551336464017708
20 34806599282992709341
21 1043452963148195577181

List of values

[1, 1, 1, 4, 13, 61, 421, 2626, 27049, 245953, 3069721, 40222216, 576988501, 10058716669, 169773404893, 3596206855606, 73450508303761, 1775382487932001, 43993288886533489, 1183551336464017708, 34806599282992709341, 1043452963148195577181]