a(n) = 56*n^2 + 1.

Terms

a(0) =1a(1) =57a(2) =225a(3) =505a(4) =897a(5) =1401a(6) =2017a(7) =2745a(8) =3585a(9) =4537a(10) =5601a(11) =6777a(12) =8065a(13) =9465a(14) =10977a(15) =12601a(16) =14337a(17) =16185a(18) =18145a(19) =20217a(20) =22401a(21) =24697a(22) =27105a(23) =29625a(24) =32257a(25) =35001a(26) =37857a(27) =40825a(28) =43905a(29) =47097