Even heptagonal numbers (A000566).

Terms

a(0) =0a(1) =18a(2) =34a(3) =112a(4) =148a(5) =286a(6) =342a(7) =540a(8) =616a(9) =874a(10) =970a(11) =1288a(12) =1404a(13) =1782a(14) =1918a(15) =2356a(16) =2512a(17) =3010a(18) =3186a(19) =3744a(20) =3940a(21) =4558a(22) =4774a(23) =5452a(24) =5688a(25) =6426a(26) =6682a(27) =7480a(28) =7756a(29) =8614