a(n) = A213493(n)/12.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =4a(8) =8a(9) =17a(10) =25a(11) =40a(12) =57a(13) =81a(14) =105a(15) =141a(16) =177a(17) =225a(18) =274a(19) =337a(20) =401a(21) =482a(22) =562a(23) =661a(24) =762a(25) =882a(26) =1002a(27) =1146a(28) =1290a(29) =1458