a(n) = A020639(A004094(n)).

Terms

a(0) =1a(1) =2a(2) =2a(3) =2a(4) =61a(5) =23a(6) =2a(7) =821a(8) =2a(9) =5a(10) =4201a(11) =2a(12) =2a(13) =2a(14) =137a(15) =7a(16) =2a(17) =270131a(18) =2a(19) =5a(20) =13a(21) =2a(22) =2a(23) =2a(24) =61277761a(25) =17a(26) =2a(27) =7a(28) =2a(29) =5