18522n - 42.

Terms

a(0) =18480a(1) =37002a(2) =55524a(3) =74046a(4) =92568a(5) =111090a(6) =129612a(7) =148134a(8) =166656a(9) =185178a(10) =203700a(11) =222222a(12) =240744a(13) =259266a(14) =277788a(15) =296310a(16) =314832a(17) =333354a(18) =351876a(19) =370398a(20) =388920a(21) =407442a(22) =425964a(23) =444486a(24) =463008a(25) =481530a(26) =500052a(27) =518574a(28) =537096a(29) =555618