OFFSET
1,1
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..174
D. Shanks, Generalized Euler and class numbers. Math. Comp. 21 (1967) 689-694.
D. Shanks, Corrigenda to: "Generalized Euler and class numbers", Math. Comp. 22 (1968), 699.
Eric Weisstein's World of Mathematics, Tangent Number.
FORMULA
a(n) = (2*n-1)!*[x^(2*n-1)](sec(9*x)*4*sin(3*x)*cos(3*x)^2). - Peter Luschny, Nov 21 2021
MAPLE
egf := sec(9*x)*4*sin(3*x)*cos(3*x)^2: ser := series(egf, x, 24):
seq((2*n-1)!*coeff(ser, x, 2*n-1), n = 1..10); # Peter Luschny, Nov 21 2021
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Aug 31 2001
EXTENSIONS
Offset changed to 1 by Lars Blomberg, Sep 07 2015
STATUS
approved