a(n) = (n + 1)^2*(5*n^2 + 10*n + 2)/2.

Terms

a(0) =1a(1) =34a(2) =189a(3) =616a(4) =1525a(5) =3186a(6) =5929a(7) =10144a(8) =16281a(9) =24850a(10) =36421a(11) =51624a(12) =71149a(13) =95746a(14) =126225a(15) =163456a(16) =208369a(17) =261954a(18) =325261a(19) =399400a(20) =485541a(21) =584914a(22) =698809a(23) =828576a(24) =975625a(25) =1141426a(26) =1327509a(27) =1535464a(28) =1766941a(29) =2023650