Coefficient of q^2 in nu(n), where nu(0)=1, nu(1)=b and, for n>=2, nu(n)=b*nu(n-1)+lambda*(1+q+q^2+...+q^(n-2))*nu(n-2) with (b,lambda)=(1,1).

A074082

Coefficient of q^2 in nu(n), where nu(0)=1, nu(1)=b and, for n>=2, nu(n)=b*nu(n-1)+lambda*(1+q+q^2+...+q^(n-2))*nu(n-2) with (b,lambda)=(1,1).

Terms

    a(0) =0a(1) =0a(2) =0a(3) =0a(4) =2a(5) =6a(6) =16a(7) =37a(8) =81a(9) =169a(10) =342a(11) =675a(12) =1307a(13) =2491a(14) =4686a(15) =8718a(16) =16066a(17) =29364a(18) =53282a(19) =96065a(20) =172215a(21) =307151a(22) =545286a(23) =963993a(24) =1697701a(25) =2979383a(26) =5211852a(27) =9090060a(28) =15810530a(29) =27429426

External references