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A064068
Generalized Euler number c(7,n).
6
1, 64, 15872, 9493504, 10562158592, 18878667833344, 49488442978598912, 178867627497727197184, 852509723495811705208832, 5180564635674867885905281024, 39094622102339738427522497380352, 358686739310560735577543742129700864, 3931974790759726002374736527410407145472
OFFSET
0,2
LINKS
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, Euler Number.
FORMULA
a(n) = (2*n)!*[x^(2*n)](sec(7*x)*(cos(x) + cos(3*x) - cos(5*x))). - Peter Luschny, Nov 21 2021
MAPLE
egf := sec(7*x)*(cos(x) + cos(3*x) - cos(5*x)): ser := series(egf, x, 24):
seq((2*n)!*coeff(ser, x, 2*n), n = 0..11); # Peter Luschny, Nov 21 2021
MATHEMATICA
Range[0, 24, 2]! CoefficientList[Series[Sec[7 x] (Cos[x] + Cos[3 x] - Cos[5 x]), {x, 0, 24}], x^2] (* Matthew House, Oct 25 2024 *)
CROSSREFS
Row 7 of A235605.
Sequence in context: A016794 A264058 A123051 * A220853 A013781 A330482
KEYWORD
nonn,easy
AUTHOR
Eric W. Weisstein, Aug 31 2001
STATUS
approved