a(n) = A000217(n)*A000045(n).

Terms

a(0) =0a(1) =1a(2) =3a(3) =12a(4) =30a(5) =75a(6) =168a(7) =364a(8) =756a(9) =1530a(10) =3025a(11) =5874a(12) =11232a(13) =21203a(14) =39585a(15) =73200a(16) =134232a(17) =244341a(18) =441864a(19) =794390a(20) =1420650a(21) =2528526a(22) =4480883a(23) =7909332a(24) =13910400a(25) =24383125a(26) =42608943a(27) =74246004a(28) =129031266a(29) =223689615