本帖最后由 elim 于 2014-8-20 20:55 编辑
例: p(1)=5, p(2) = 17, f(p,k) = {p+k+2000 的最大素因子}, p(n+2) = f(p(n), p(n+1))
由 ref 知如此得到的序列有界:
5,17,337,107,47,359,401,23,101,59,5,43,2,409,2411,241,1163,37,5,1021,89,311,5,193,157,47,29,173,367,127,43,31,61,523,19,41,103,67,31,1049,11,17,13,29,1021,61,67,19,149,271,11,163,1087,13,31,73,263,73,73,37,211,281,89,79,271,47,61,31,523,1277,19,103,1061,113,23,89,11,7,1009,29,31,103,97,11,31,1021,109,313,173,113,127,7,97,263,59,43,1051,17,59,173,31,29,103,41,67,31,1049,11,17,13,29,1021,61,67,19,149,271,11,163,1087,13,31,73,263,73,73,37,211,281,89,79,271,47,61,31,523,1277,19,103,1061,113,23,89,11,7,1009,29,31,103,97,11,31,1021,109,313,173,113,127,7,97,263,59,43,1051,17,59,173,31,29,103,41,.........
可见不计前有限项,这是一个循环序列。 |