a(n) = binomial(n+8,8) - 1.

Terms

a(0) =0a(1) =8a(2) =44a(3) =164a(4) =494a(5) =1286a(6) =3002a(7) =6434a(8) =12869a(9) =24309a(10) =43757a(11) =75581a(12) =125969a(13) =203489a(14) =319769a(15) =490313a(16) =735470a(17) =1081574a(18) =1562274a(19) =2220074a(20) =3108104a(21) =4292144a(22) =5852924a(23) =7888724a(24) =10518299a(25) =13884155a(26) =18156203a(27) =23535819a(28) =30260339a(29) =38608019