Binomial(sigma(n),omega(n)), where sigma(n) is the sum of divisors of n (A000203) and omega the number of distinct prime factors (A001221).

A068905

Binomial(sigma(n),omega(n)), where sigma(n) is the sum of divisors of n (A000203) and omega the number of distinct prime factors (A001221).

Terms

    a(0) =1a(1) =3a(2) =4a(3) =7a(4) =6a(5) =66a(6) =8a(7) =15a(8) =13a(9) =153a(10) =12a(11) =378a(12) =14a(13) =276a(14) =276a(15) =31a(16) =18a(17) =741a(18) =20a(19) =861a(20) =496a(21) =630a(22) =24a(23) =1770a(24) =31a(25) =861a(26) =40a(27) =1540a(28) =30a(29) =59640

External references