-26567

Appears in sequences

• E.g.f.: sech(exp(x)-cos(x)).at n=8A013321
• a(n) = a(n-2) - 2*a(n-3) + a(n-4) for n>3, a(0)=0, a(1)=2, a(2)=-1, a(3)=3.at n=22A286390