a(n) = n^3 + sum((-1)^j*a(j)); for j=1 to n-1; a(1)=1.

Terms

a(0) =1a(1) =7a(2) =33a(3) =37a(4) =135a(5) =91a(6) =309a(7) =169a(8) =555a(9) =271a(10) =873a(11) =397a(12) =1263a(13) =547a(14) =1725a(15) =721a(16) =2259a(17) =919a(18) =2865a(19) =1141a(20) =3543a(21) =1387a(22) =4293a(23) =1657a(24) =5115a(25) =1951a(26) =6009a(27) =2269a(28) =6975a(29) =2611