a(n) = (6*n+1)*(6*n+5).

Terms

a(0) =5a(1) =77a(2) =221a(3) =437a(4) =725a(5) =1085a(6) =1517a(7) =2021a(8) =2597a(9) =3245a(10) =3965a(11) =4757a(12) =5621a(13) =6557a(14) =7565a(15) =8645a(16) =9797a(17) =11021a(18) =12317a(19) =13685a(20) =15125a(21) =16637a(22) =18221a(23) =19877a(24) =21605a(25) =23405a(26) =25277a(27) =27221a(28) =29237a(29) =31325