3 times 10-gonal (or decagonal) numbers: a(n) = 3*n*(4*n-3).

Terms

a(0) =0a(1) =3a(2) =30a(3) =81a(4) =156a(5) =255a(6) =378a(7) =525a(8) =696a(9) =891a(10) =1110a(11) =1353a(12) =1620a(13) =1911a(14) =2226a(15) =2565a(16) =2928a(17) =3315a(18) =3726a(19) =4161a(20) =4620a(21) =5103a(22) =5610a(23) =6141a(24) =6696a(25) =7275a(26) =7878a(27) =8505a(28) =9156a(29) =9831