A395274 a(n) = (2*n)! * [x^(2*n)] cos(3*x) * cos(4*x) / cos(12*x).

1, 119, 83281, 145800359, 476505209761, 2502838476144599, 19280997072330355441, 204797011339726937324039, 2868518098265007506767936321, 51227334488880915770157520378679, 1136077852491071055019123212221408401, 30631820404953071010639678870096430748519

Offset

0,2

Links

Table of n, a(n) for n=0..11.

Formula

a(n) = (-1)^n * (49^n + 1)/2 - Sum_{k=0..n-1} (-144)^(n-k) * binomial(2*n,2*k) * a(k).

Prog

(PARI) a_vector(n, s=3, t=4) = my(v=vector(n+1)); for(i=0, n, v[i+1]=(-1)^i*((s+t)^(2*i)+(s-t)^(2*i))/2-sum(j=0, i-1, (-(s*t)^2)^(i-j)*binomial(2*i, 2*j)*v[j+1])); v;

Crossrefs

Cf. A352977.

Sequence in context: A020546 A323318 A192726 * A266032 A269123 A336171

Adjacent sequences: A395271 A395272 A395273 * A395275 A395276 A395277

Keyword

nonn

Author

Seiichi Manyama, Apr 18 2026

Status

approved