G.f. A(x) = exp( Sum_{n>=1} sigma(n)*sigma(2*n)/3 * x^n/n ), where sigma(n) = A000203(n) is the sum of the divisors of n.
A382124
G.f. A(x) = exp( Sum_{n>=1} sigma(n)*sigma(2*n)/3 * x^n/n ), where sigma(n) = A000203(n) is the sum of the divisors of n.
Terms
- a(0) =1a(1) =1a(2) =4a(3) =9a(4) =22a(5) =44a(6) =105a(7) =200a(8) =425a(9) =825a(10) =1634a(11) =3072a(12) =5917a(13) =10846a(14) =20153a(15) =36436a(16) =65882a(17) =116831a(18) =207293a(19) =361502a(20) =629539a(21) =1083068a(22) =1856251a(23) =3150554a(24) =5328137a(25) =8933266a(26) =14920357a(27) =24745481a(28) =40869317a(29) =67089425
External references
- oeis: A382124