Second hexagonal numbers: a(n) = n*(2*n + 1).

Terms

a(0) =0a(1) =3a(2) =10a(3) =21a(4) =36a(5) =55a(6) =78a(7) =105a(8) =136a(9) =171a(10) =210a(11) =253a(12) =300a(13) =351a(14) =406a(15) =465a(16) =528a(17) =595a(18) =666a(19) =741a(20) =820a(21) =903a(22) =990a(23) =1081a(24) =1176a(25) =1275a(26) =1378a(27) =1485a(28) =1596a(29) =1711