login
A074923
Number of steps to reach the first integer starting with prime(n+1)/prime(n) and iterating the map x -> x*ceiling(x), or -1 if no integer is ever reached.
0
1, 6, 18, 5, 5, 7, 37, 132, 29, 63, 46, 11, 7, 212, 25, 38, 145, 136, 46, 118, 39, 37, 24, 15, 19, 85, 211, 179, 249, 266, 190, 87, 259, 216, 16, 70, 210, 56, 255, 94, 143, 244, 482, 558, 46, 327, 271, 93, 110, 8, 121, 29, 421, 329, 47, 40, 394, 376, 64, 249, 49, 390, 321
OFFSET
1,2
EXAMPLE
a(4)=5 since A000040(4+1)/A000040(4)=11/7 -> 22/7 -> 88/7 -> 1144/7 -> 187616/7 -> 718381664.
CROSSREFS
Sequence in context: A376134 A355787 A077022 * A093061 A264028 A078741
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 04 2002
EXTENSIONS
Extended by Max Alekseyev, Jul 28 2009
STATUS
approved