a(n) is the number of conjugacy classes in the alternating group A_n.

Terms

a(0) =1a(1) =1a(2) =3a(3) =4a(4) =5a(5) =7a(6) =9a(7) =14a(8) =18a(9) =24a(10) =31a(11) =43a(12) =55a(13) =72a(14) =94a(15) =123a(16) =156a(17) =200a(18) =254a(19) =324a(20) =408a(21) =513a(22) =641a(23) =804a(24) =997a(25) =1236a(26) =1526a(27) =1883a(28) =2308a(29) =2829