Second-order spt function.

Terms

a(0) =0a(1) =1a(2) =5a(3) =15a(4) =35a(5) =75a(6) =140a(7) =259a(8) =435a(9) =735a(10) =1155a(11) =1841a(12) =2765a(13) =4200a(14) =6125a(15) =8975a(16) =12731a(17) =18179a(18) =25235a(19) =35180a(20) =48055a(21) =65681a(22) =88299a(23) =118895a(24) =157690a(25) =209230a(26) =274510a(27) =359779a(28) =466970a(29) =605740