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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.

A307878 Expansion of e.g.f. exp(3*x)*(sec(x) + tan(x)).

Table of values

n a(n)
0 1
1 4
2 16
3 65
4 272
5 1189
6 5506
7 27365
8 147512
9 868129
10 5589646
11 39309965
12 300724652
13 2489776969
14 22192420786
15 211923843365
16 2158631018192
17 23361793658209
18 267706067651926
19 3238110860029565
20 41228900865842132
21 551189774407729849
22 7719762678323791066

List of values

[1, 4, 16, 65, 272, 1189, 5506, 27365, 147512, 868129, 5589646, 39309965, 300724652, 2489776969, 22192420786, 211923843365, 2158631018192, 23361793658209, 267706067651926, 3238110860029565, 41228900865842132, 551189774407729849, 7719762678323791066]

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

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