Primitive part of A001353(n).

Terms

a(0) =1a(1) =4a(2) =15a(3) =14a(4) =209a(5) =13a(6) =2911a(7) =194a(8) =2703a(9) =181a(10) =564719a(11) =193a(12) =7865521a(13) =2521a(14) =34945a(15) =37634a(16) =1525870529a(17) =2701a(18) =21252634831a(19) =37441a(20) =6779137a(21) =489061a(23) =37633a(24) =274758906449a(25) =6811741a(26) =19726764303a(27) =7263361a(29) =40321