a(n) = n*(14*n + 13) + 3.

Terms

a(0) =3a(1) =30a(2) =85a(3) =168a(4) =279a(5) =418a(6) =585a(7) =780a(8) =1003a(9) =1254a(10) =1533a(11) =1840a(12) =2175a(13) =2538a(14) =2929a(15) =3348a(16) =3795a(17) =4270a(18) =4773a(19) =5304a(20) =5863a(21) =6450a(22) =7065a(23) =7708a(24) =8379a(25) =9078a(26) =9805a(27) =10560a(28) =11343a(29) =12154