a(n) = 144*n^2 - 161*n + 45.

Terms

a(0) =28a(1) =299a(2) =858a(3) =1705a(4) =2840a(5) =4263a(6) =5974a(7) =7973a(8) =10260a(9) =12835a(10) =15698a(11) =18849a(12) =22288a(13) =26015a(14) =30030a(15) =34333a(16) =38924a(17) =43803a(18) =48970a(19) =54425a(20) =60168a(21) =66199a(22) =72518a(23) =79125a(24) =86020a(25) =93203a(26) =100674a(27) =108433a(28) =116480a(29) =124815