a(n) = (n + 2)*(5*n + 1)/2.

Terms

a(0) =1a(1) =9a(2) =22a(3) =40a(4) =63a(5) =91a(6) =124a(7) =162a(8) =205a(9) =253a(10) =306a(11) =364a(12) =427a(13) =495a(14) =568a(15) =646a(16) =729a(17) =817a(18) =910a(19) =1008a(20) =1111a(21) =1219a(22) =1332a(23) =1450a(24) =1573a(25) =1701a(26) =1834a(27) =1972a(28) =2115a(29) =2263