-2641

Appears in sequences

• Expansion of e.g.f. sin(sin(x)/cosh(x)), odd powers only.at n=3A009485
• a(n) = -a(n-1) + 2*a(n-2) + a(n-3), a(0) = -1, a(1) = -2, a(2) = 3.at n=13A321175