13 times pentagonal numbers: a(n) = 13*n*(3*n-1)/2.

Terms

a(0) =0a(1) =13a(2) =65a(3) =156a(4) =286a(5) =455a(6) =663a(7) =910a(8) =1196a(9) =1521a(10) =1885a(11) =2288a(12) =2730a(13) =3211a(14) =3731a(15) =4290a(16) =4888a(17) =5525a(18) =6201a(19) =6916a(20) =7670a(21) =8463a(22) =9295a(23) =10166a(24) =11076a(25) =12025a(26) =13013a(27) =14040a(28) =15106a(29) =16211