这个数列叫做 The Collatz or 3x+1 function 他的公式为a(n) = n/2 if n is even,otherwise (3n+1)/2 0,2,1 ,5 ,2 ,8 ,3 ,11 ,4 ,14 ,5,17,6,20,7,23,8,26,9,29,10,32,11,35,12,38,13,41,14,44,15,47,16,50,17,53,18,56,19,59,20,62,21,65,22,68,23,71,24,74,25,77,26,80,27,83,28,86,29,89,30,92,31,95,32,98,33,101,34,104