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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.

A190195 Numerators of a Taylor series expansion of 1/sqrt(cosh(x)) (even powers only).

Table of values

n a(n)
0 1
1 -1
2 7
3 -139
4 5473
5 -51103
6 34988647
7 -4784061619
8 17782347217
9 -203906055033841
10 4586025046220899
11 -234038275571853889
12 9127322584507530151393
13 -4621897483978366951337161
14 390009953658229908025520161
15 -1860452328661957054823447670979
16 111446346975327291562408943638981
17 -14050053632877769956552601074149491
18 1269258883676324618437848731917951368967
19 -1408182090109327874242950762763137949746859

List of values

[1, -1, 7, -139, 5473, -51103, 34988647, -4784061619, 17782347217, -203906055033841, 4586025046220899, -234038275571853889, 9127322584507530151393, -4621897483978366951337161, 390009953658229908025520161, -1860452328661957054823447670979, 111446346975327291562408943638981, -14050053632877769956552601074149491, 1269258883676324618437848731917951368967, -1408182090109327874242950762763137949746859]

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

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