Expansion of Product_{k>=1} (1 + sigma(k)*x^k), where sigma(k) is the sum of the divisors of k (A000203).

A316962

Expansion of Product_{k>=1} (1 + sigma(k)*x^k), where sigma(k) is the sum of the divisors of k (A000203).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =7a(4) =11a(5) =25a(6) =51a(7) =87a(8) =129a(9) =286a(10) =462a(11) =760a(12) =1312a(13) =2102a(14) =3470a(15) =5988a(16) =8840a(17) =13884a(18) =22577a(19) =33545a(20) =55961a(21) =85341a(22) =126705a(23) =194317a(24) =293621a(25) =435040a(26) =641472a(27) =971503a(28) =1462483a(29) =2108161

External references