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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.

A012467 Expansion of e.g.f. sech(arctan(x)^2), even powers only.

Table of values

n a(n)
0 1
1 0
2 -12
3 480
4 -21168
5 741120
6 61942848
7 -29951061504
8 8015861467392
9 -1745546459848704
10 215844160641143808
11 91751419512905687040
12 -109687232118939992862720
13 71900040403600384794624000
14 -32879657977585141660017868800
15 2569990403264790442179575808000

List of values

[1, 0, -12, 480, -21168, 741120, 61942848, -29951061504, 8015861467392, -1745546459848704, 215844160641143808, 91751419512905687040, -109687232118939992862720, 71900040403600384794624000, -32879657977585141660017868800, 2569990403264790442179575808000]

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

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