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.

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

Links

Table of n, a(n) for n=1..63.

Example

a(4)=5 since A000040(4+1)/A000040(4)=11/7 -> 22/7 -> 88/7 -> 1144/7 -> 187616/7 -> 718381664.

Crossrefs

Cf. A073524, A000040.

Sequence in context: A209341 A355787 A077022 * A093061 A264028 A078741

Adjacent sequences: A074920 A074921 A074922 * A074924 A074925 A074926

Keyword

nonn

Author

Reinhard Zumkeller, Oct 04 2002

Extensions

Extended by Max Alekseyev, Jul 28 2009

Status

approved