a:= proc(n) option remember; `if`(n<9, [1, 2, 8, 39, 212, 1230, 7458, 46689, 299463][n+1], ((n+1)*(396037*n^8 -6294739*n^7 +26829987*n^6 +38888351*n^5 -532849152*n^4 +1223707844*n^3 -887604952*n^2 +70624704*n -49593600)*a(n-1) +(148780800 -32046628*n^6 +3044601492*n^5 -10503304912*n^4 +15032446808*n^3 -9306985812*n^2 -169105548*n^7 +32702672*n^8 -1891520*n^9 +1727555688*n)*a(n-2) +(9470865600 -130628926*n^6 -4458372806*n^5 +23279528426*n^4 -54678890084*n^3 +67424318096*n^2+213207454*n^7-34152156*n^8+1773300*n^9 -41322510024*n)*a(n-3) +(502891200 -500533872*n^6 -1171774512*n^5 +11591926932*n^4 -30969786508*n^3 +36996249612*n^2 +177666348*n^7 -21647592*n^8 +945760*n^9 -17219569608*n)*a(n-4) +(-33121872000 +523021966*n^6 +3257473624*n^5 -28607413766*n^4 +92113975084*n^3 -148741566536*n^2 -210226154*n^7 +24621696*n^8 -1028514*n^9 +115911224520*n)*a(n-5) +(-14670936000 +519170140*n^6 +686540100*n^5 -13745279000*n^4 +50903424440*n^3 -85285417140*n^2 -132408540*n^7 +12975400*n^8 -472880*n^9 +63360652680*n)*a(n-6) +2*(n-7)*(82754*n^8 -1720972*n^7 +11297091*n^6 -190018*n^5 -339345249*n^4 +1704091082*n^3 -3633910196*n^2 +3474850308*n -1182535200)*a(n-7) +2*(n-7)*(n-8)* (59110*n^7 -959893*n^6 +3867412*n^5 +12759230*n^4 -134719970*n^3 +353227073*n^2 -357138942*n +113599800)*a(n-8) +3*(n-7)*(n-8)*(n-9)* (5911*n^6 -58750*n^5 +24085*n^4 +1326290*n^3 -4534256*n^2 +5027600*n -1599000)*a(n-9))/ (2*(2*n+1)*(n+2)*(n+1)*(5911*n^6 -94216*n^5 +406500*n^4 +524230*n^3 -7692451*n^2 +17649426*n -12398400))) end: seq (a(n), n=0..30);