G.f.: exp( Sum_{n>=1} 3 * Jacobsthal(n)^2 * x^n/n ), where Jacobsthal(n) = A001045(n).

A211894

G.f.: exp( Sum_{n>=1} 3 * Jacobsthal(n)^2 * x^n/n ), where Jacobsthal(n) = A001045(n).

Terms

    a(0) =1a(1) =3a(2) =6a(3) =18a(4) =57a(5) =195a(6) =684a(7) =2460a(8) =8970a(9) =33102a(10) =123204a(11) =461868a(12) =1741410a(13) =6597750a(14) =25099584a(15) =95822928a(16) =366943881a(17) =1408947675a(18) =5422742910a(19) =20915079258a(20) =80820382425a(21) =312839889219

External references