Thickened pyramidal numbers: a(n) = 2*(n+1)*n + Sum_{i=1..n} (4*i*(i-1) + 1).

Terms

a(0) =0a(1) =5a(2) =22a(3) =59a(4) =124a(5) =225a(6) =370a(7) =567a(8) =824a(9) =1149a(10) =1550a(11) =2035a(12) =2612a(13) =3289a(14) =4074a(15) =4975a(16) =6000a(17) =7157a(18) =8454a(19) =9899a(20) =11500a(21) =13265a(22) =15202a(23) =17319a(24) =19624a(25) =22125a(26) =24830a(27) =27747a(28) =30884a(29) =34249