[20/2]+[20/4]+[20/8]+[20/16]=10+5+2+1=18,所以20!分解式中含2^18.同理有含3^8,5^4,7^1,11^1,13^1,17^1,19^1.15!含2^11,3^6,5^3,7^2,11^1,13^1.所以合起来是2^29,3^14,5^7,7^3,11^2,13^2,17^1,19^1.关键是掌握算阶...