Empirical: a(n) = (1/1656632731900575744000000)*n^28 + (1/23666181884293939200000)*n^27 + (197/76740680486486016000000)*n^26 + (191951/1880146671918907392000000)*n^25 + (7946527/2256176006302688870400000)*n^24 + (1503431/15041173375351259136000)*n^23 + (6490149623/2517761630221841203200000)*n^22 + (2869187099/49047304484841062400000)*n^21 + (17244728801/14013515567097446400000)*n^20 + (75135493547/3269820298989404160000)*n^19 + (2155814659109/5162874156299059200000)*n^18 + (5153254826101/860479026049843200000)*n^17 + (207659181456407/2125889358476083200000)*n^16 + (8712634636231/30369847978229760000)*n^15 + (203016953797057/6197928158822400000)*n^14 - (924979865456093/4601492117913600000)*n^13 + (90702894734870589571/14197903929822412800000)*n^12 - (1464845746168698967/43023951302492160000)*n^11 + (75805769618145177203353/128749174272707788800000)*n^10 - (21987491942680503592807/9196369590907699200000)*n^9 + (26992062232273400774023/1094805903679488000000)*n^8 - (24794932990162999879711/255454710858547200000)*n^7 + (781558326336701679916651/1224053822863872000000)*n^6 - (268038043963217961282893/102004485238656000000)*n^5 + (30428503889127494898091/2380104655568640000)*n^4 - (40855116344732385853/539706271104000)*n^3 + (2318656934226364141/5936768982144)*n^2 - (225397425874997/1115464350)*n - 3602498 for n>9