A074808 Let f(n) be 2n + POD(n) + 1 if n is even, otherwise 2n - POD(n) - 1, where POD(n) is the product of digits of n. Sequence gives smallest number requiring n iterations to reach a prime.

2, 1, 13, 8, 9, 34, 86, 51, 113, 348, 193, 152, 80, 199, 736, 579, 448, 502, 446, 281, 339, 532, 1521, 760, 438, 371, 971, 524, 1642, 988, 1613, 6856, 4494, 5146, 2793, 1348, 3916, 5531, 6544, 3570, 7982, 6415, 3211, 1633, 11634, 9462

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Example

a(3) = 13 because 13 -(1)-> 22 -(2)-> 49 -(3)-> 61.

Crossrefs

Sequence in context: A167584 A112226 A192795 * A113097 A032001 A358205

Adjacent sequences: A074805 A074806 A074807 * A074809 A074810 A074811

Keyword

base,nonn

Author

Jason Earls, Sep 08 2002

Status

approved