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Generalized Euler numbers, a(n) = n!*[x^n](sec(9*x)*(4*sin(3*x) + 2)*cos(3*x)^2).
5

%I #13 Oct 31 2024 02:41:20

%S 2,12,126,2160,49410,1415232,48649086,1951153920,89434106370,

%T 4611775398912,264235243691646,16653520425185280,1145011717430672130,

%U 85285640517460180992,6841110155700330881406,587950108643300554506240,53899295662946509072626690,5249943672359370392053481472

%N Generalized Euler numbers, a(n) = n!*[x^n](sec(9*x)*(4*sin(3*x) + 2)*cos(3*x)^2).

%C For references and cross references, compare the overview in A349264.

%H Matthew House, <a href="/A349268/b349268.txt">Table of n, a(n) for n = 0..348</a>

%p sec(9*x)*(4*sin(3*x) + 2)*cos(3*x)^2: series(%, x, 20): seq(n!*coeff(%, x, n), n = 0..17);

%t m = 17; CoefficientList[Series[Sec[9*x] * (4 * Sin[3*x] + 2) * Cos[3*x]^2, {x, 0, m}], x] * Range[0, m]! (* _Amiram Eldar_, Nov 21 2021 *)

%Y Row 9 of A349271.

%Y Bisections: A064070, A064074.

%Y Cf. A349264.

%K nonn,changed

%O 0,1

%A _Peter Luschny_, Nov 21 2021