a(0) = 0, and for n > 0, a(n) = A002956(n) - A000041(n).

Terms

a(0) =0a(1) =0a(2) =0a(3) =1a(4) =2a(5) =8a(6) =9a(7) =33a(8) =43a(9) =89a(10) =124a(11) =292a(12) =290a(13) =726a(14) =839a(15) =1318a(16) =1904a(17) =3616a(18) =3653a(19) =7446a(20) =7620a(21) =12175a(22) =16474a(23) =27907a(24) =26490a(25) =47651a(26) =56922a(27) =80410a(28) =93525a(29) =160402