a(n) = binomial(n,11).

Terms

a(0) =1a(1) =12a(2) =78a(3) =364a(4) =1365a(5) =4368a(6) =12376a(7) =31824a(8) =75582a(9) =167960a(10) =352716a(11) =705432a(12) =1352078a(13) =2496144a(14) =4457400a(15) =7726160a(16) =13037895a(17) =21474180a(18) =34597290a(19) =54627300a(20) =84672315a(21) =129024480a(22) =193536720a(23) =286097760a(24) =417225900a(25) =600805296a(26) =854992152a(27) =1203322288a(28) =1676056044