a(n) = 13*n^2 + 10*n + 3.

Terms

a(0) =3a(1) =26a(2) =75a(3) =150a(4) =251a(5) =378a(6) =531a(7) =710a(8) =915a(9) =1146a(10) =1403a(11) =1686a(12) =1995a(13) =2330a(14) =2691a(15) =3078a(16) =3491a(17) =3930a(18) =4395a(19) =4886a(20) =5403a(21) =5946a(22) =6515a(23) =7110a(24) =7731a(25) =8378a(26) =9051a(27) =9750a(28) =10475a(29) =11226