>>257, 261, 276, 283

(1) 11回目
(2) (5^3*7)/(2^7*3^4) = 0.08439429…
(3) 11, 10, 12, 13, 9, 14, 15, 8, 16, 17.

p(1) = p(2) = p(3) = p(4) = p(5) = 0, p(6) = 120/(6^6),

期待値 14.7(回)

漸化式
 p(n) = (15/6)p(n-1) - (85/6^2)p(n-2) + (225/6^3)p(n-3) - (274/6^4)p(n-4)+ (120/6^5)p(n-5),

生成関数
 G(x) = 120 x^6/{(6-x)(6-2x)(6-3x)(6-4x)(6-5x)}
   = p(6) x^6/{1 - 15(x/6) + 85(x/6)^2 - 225(x/6)^3 + 274(x/6)^4 - 120(x/6)^5},