n+8*C(n,2)+30*C(n,3)+62*C(n,4)+75*C(n,5)+30*C(n,6).

Terms

a(0) =0a(1) =1a(2) =10a(3) =57a(4) =234a(5) =770a(6) =2136a(7) =5180a(8) =11292a(9) =22599a(10) =42190a(11) =74371a(12) =124950a(13) =201552a(14) =313964a(15) =474510a(16) =698456a(17) =1004445a(18) =1414962a(19) =1956829a(20) =2661730a(21) =3566766a(22) =4715040a(23) =6156272a(24) =7947444a(25) =10153475a(26) =12847926a(27) =16113735a(28) =20043982a(29) =24742684