a(n) = n*(8*n - 3).

Terms

a(0) =0a(1) =5a(2) =26a(3) =63a(4) =116a(5) =185a(6) =270a(7) =371a(8) =488a(9) =621a(10) =770a(11) =935a(12) =1116a(13) =1313a(14) =1526a(15) =1755a(16) =2000a(17) =2261a(18) =2538a(19) =2831a(20) =3140a(21) =3465a(22) =3806a(23) =4163a(24) =4536a(25) =4925a(26) =5330a(27) =5751a(28) =6188a(29) =6641