OFFSET
0,1
LINKS
Matthew House, Table of n, a(n) for n = 0..171
Eric Weisstein's World of Mathematics, Euler Number.
Daniel Shanks, Generalized Euler and class numbers, Mathematics of Computation, Vol. 21, No. 100 (1967), pp. 689-694; Corrigenda, ibid., Vol. 22, No. 103 (1968), p. 699.
FORMULA
a(n) = (2*n)!*[x^(2*n)](sec(10*x)*(cos(x) + cos(3*x) - cos(7*x) + cos(9*x))). - Matthew House, Oct 27 2024
MATHEMATICA
Range[0, 18, 2]! CoefficientList[Series[Sec[10 x] (Cos[x] + Cos[3 x] - Cos[7 x] + Cos[9 x]), {x, 0, 18}], x^2] (* Matthew House, Oct 27 2024 *)
CROSSREFS
KEYWORD
nonn,easy,changed
AUTHOR
Eric W. Weisstein, Aug 31 2001
STATUS
approved