14 times triangular numbers.

Terms

a(0) =0a(1) =14a(2) =42a(3) =84a(4) =140a(5) =210a(6) =294a(7) =392a(8) =504a(9) =630a(10) =770a(11) =924a(12) =1092a(13) =1274a(14) =1470a(15) =1680a(16) =1904a(17) =2142a(18) =2394a(19) =2660a(20) =2940a(21) =3234a(22) =3542a(23) =3864a(24) =4200a(25) =4550a(26) =4914a(27) =5292a(28) =5684a(29) =6090