OFFSET
1,1
EXAMPLE
252 is factored as 2^2 * 3^2 * 7^1. Since 2^2 > 3 and 3^2 > 7, then 252 is in the sequence. On the other hand, 60 is factored as 2^2 * 3^1 * 5^1. Even though 2^2 > 3, 3^1 is not > 5. So 60 is not in the sequence.
PROG
(PARI) isok(n) = {my(f = factor(n)); if (#f~ == 1, return (0)); for (i=1, #f~ - 1, if (f[i, 1]^f[i, 2] <= f[i+1, 1], return (0)); ); return (1); } \\ Michel Marcus, Jan 19 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Leroy Quet, Sep 04 2008
EXTENSIONS
Extended by Ray Chandler, Nov 06 2008
STATUS
approved