排列组合题一道，懂的进。

satgo1546

awedcvgyujm 发表于 2014-3-8 16:08
等价于解
(1+x+x^2+x^3+x^4)^13*(1+x)^2
中x^17项的系数

好可怕……

无法直视的结果：

1. (x^54)+15*x^53+118*x^52+650*x^51+2821*x^50+10270*x^49+32565*x^48+92170*x^47+236860*x^46+559585*x^45+1226875*x^44+2514590*x^43+4846010*x^42+8822360*x^41+15231140*x^40+25015160*x^39+39187265*x^38+58684015*x^37+84166160*x^36+115792300*x^35+153009740*x^34+194417015*x^33+237750305*x^32+280028060*x^31+317856305*x^30+347858303*x^29+367156960*x^28+373817264*x^27+367156960*x^26+347858303*x^25+317856305*x^24+280028060*x^23+237750305*x^22+194417015*x^21+153009740*x^20+115792300*x^19+84166160*x^18+58684015*x^17+39187265*x^16+25015160*x^15+15231140*x^14+8822360*x^13+4846010*x^12+2514590*x^11+1226875*x^10+559585*x^9+236860*x^8+92170*x^7+32565*x^6+10270*x^5+2821*x^4+650*x^3+118*x^2+15*x+1

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