a(n) = [x^(n*(n+1)/2)] Product_{k=1..n} theta_3(q^k), where theta_3() is the Jacobi theta function.

A320931

a(n) = [x^(n*(n+1)/2)] Product_{k=1..n} theta_3(q^k), where theta_3() is the Jacobi theta function.

Terms

    a(0) =1a(1) =2a(2) =4a(3) =12a(4) =24a(5) =80a(6) =292a(7) =966a(8) =3876a(9) =15554a(10) =61608a(11) =254612a(12) =1065676a(13) =4471672a(14) =19074968a(15) =82043172a(16) =354365492a(17) =1543432514a(18) =6760146292a(19) =29732837780a(20) =131440491584a(21) =583419967664

External references