7 times pentagonal numbers: a(n) = 7*n*(3*n-1)/2.

Terms

a(0) =0a(1) =7a(2) =35a(3) =84a(4) =154a(5) =245a(6) =357a(7) =490a(8) =644a(9) =819a(10) =1015a(11) =1232a(12) =1470a(13) =1729a(14) =2009a(15) =2310a(16) =2632a(17) =2975a(18) =3339a(19) =3724a(20) =4130a(21) =4557a(22) =5005a(23) =5474a(24) =5964a(25) =6475a(26) =7007a(27) =7560a(28) =8134a(29) =8729