a(n) = A003418(n+1)*H(n), where H(n) = 1 + 1/2 + ... + 1/n is the n-th harmonic number.

Terms

a(0) =2a(1) =9a(2) =22a(3) =125a(4) =137a(5) =1029a(6) =2178a(7) =6849a(8) =7129a(9) =81191a(10) =83711a(11) =1118273a(12) =1145993a(13) =1171733a(14) =2391514a(15) =41421503a(16) =42142223a(17) =813635157a(18) =825887397a(19) =837527025a(20) =848612385a(21) =19761458895a(22) =19994251455a(23) =101086721625a(24) =102157567401a(25) =309561680403a(26) =312536252003