5 times octagonal numbers: a(n) = 5*n*(3*n-2).

Terms

a(0) =0a(1) =5a(2) =40a(3) =105a(4) =200a(5) =325a(6) =480a(7) =665a(8) =880a(9) =1125a(10) =1400a(11) =1705a(12) =2040a(13) =2405a(14) =2800a(15) =3225a(16) =3680a(17) =4165a(18) =4680a(19) =5225a(20) =5800a(21) =6405a(22) =7040a(23) =7705a(24) =8400a(25) =9125a(26) =9880a(27) =10665a(28) =11480a(29) =12325