Zero together with the partial sums of A064412.

Terms

a(0) =0a(1) =1a(2) =6a(3) =20a(4) =52a(5) =112a(6) =215a(7) =375a(8) =613a(9) =948a(10) =1407a(11) =2013a(12) =2799a(13) =3793a(14) =5034a(15) =6554a(16) =8398a(17) =10603a(18) =13220a(19) =16290a(20) =19870a(21) =24006a(22) =28761a(23) =34185a(24) =40347a(25) =47302a(26) =55125a(27) =63875a(28) =73633a(29) =84463