G.f. A(x) satisfies: A(x) = x * exp(Sum_{k>=1} (A(x^k) + sigma_2(k)*x^k)/k).

A307976

G.f. A(x) satisfies: A(x) = x * exp(Sum_{k>=1} (A(x^k) + sigma_2(k)*x^k)/k).

Terms

    a(0) =0a(1) =1a(2) =2a(3) =7a(4) =22a(5) =73a(6) =242a(7) =838a(8) =2951a(9) =10661a(10) =39169a(11) =146231a(12) =552791a(13) =2112791a(14) =8149184a(15) =31683277a(16) =124030331a(17) =488484081a(18) =1934137711a(19) =7694617999a(20) =30742092365a(21) =123294683460a(22) =496206766654

External references