a(n) = C(n+8,8) * C(n+6,6).

Terms

a(0) =1a(1) =63a(2) =1260a(3) =13860a(4) =103950a(5) =594594a(6) =2774772a(7) =11042460a(8) =38648610a(9) =121671550a(10) =350414064a(11) =935402832a(12) =2338507080a(13) =5521090680a(14) =12394285200a(15) =26606398896a(16) =54875697723a(17) =109181751525a(18) =210275965900a(19) =393175282500a(20) =715579014150