OFFSET
0,3
LINKS
FORMULA
a(n) ~ n! * c * d^n / sqrt(n), where d = 3.063838405249746742835218125232... and c = 0.308377491585051819518915209... - Vaclav Kotesovec, Aug 17 2019
MATHEMATICA
Table[n! SeriesCoefficient[(Sec[x] + Tan[x])^n, {x, 0, n}], {n, 0, 20}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jan 15 2018
STATUS
approved