a(n) = 3*n^4 + 6*n^3 - 3*n + 1.

Terms

a(0) =1a(1) =7a(2) =91a(3) =397a(4) =1141a(5) =2611a(6) =5167a(7) =9241a(8) =15337a(9) =24031a(10) =35971a(11) =51877a(12) =72541a(13) =98827a(14) =131671a(15) =172081a(16) =221137a(17) =279991a(18) =349867a(19) =432061a(20) =527941a(21) =638947a(22) =766591a(23) =912457a(24) =1078201a(25) =1265551a(26) =1476307a(27) =1712341a(28) =1975597a(29) =2268091