a(n) = binomial(n+2, 2)^4.

Terms

a(0) =1a(1) =81a(2) =1296a(3) =10000a(4) =50625a(5) =194481a(6) =614656a(7) =1679616a(8) =4100625a(9) =9150625a(10) =18974736a(11) =37015056a(12) =68574961a(13) =121550625a(14) =207360000a(15) =342102016a(16) =547981281a(17) =855036081a(18) =1303210000a(19) =1944810000a(20) =2847396321a(21) =4097152081a(22) =5802782976a(23) =8100000000a(24) =11156640625a(25) =15178486401