Number of permutations of n elements divided by the number of (binary) heaps on n+1 elements.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =9a(7) =24a(8) =45a(9) =108a(10) =189a(11) =504a(12) =945a(13) =2268a(14) =3969a(15) =12096a(16) =25515a(17) =68040a(18) =130977a(19) =381024a(20) =773955a(21) =2000376a(22) =3750705a(23) =11430720a(24) =24111675a(25) =64297800a(26) =123773265a(27) =360067680a(28) =731387475a(29) =1890355320