a(n) = (n-2)^4 - a(n-1) - a(n-2), with a(1) = a(2) = 0.

Terms

a(0) =0a(1) =0a(2) =1a(3) =15a(4) =65a(5) =176a(6) =384a(7) =736a(8) =1281a(9) =2079a(10) =3201a(11) =4720a(12) =6720a(13) =9296a(14) =12545a(15) =16575a(16) =21505a(17) =27456a(18) =34560a(19) =42960a(20) =52801a(21) =64239a(22) =77441a(23) =92576a(24) =109824a(25) =129376a(26) =151425a(27) =176175a(28) =203841a(29) =234640