OFFSET
1,1
PROG
(PARI) isok(n) = {pfs = factor(n^2-1)[, 1]; for (k = 2, n-1, if (factor(k^2-1)[, 1] == pfs, return (k)); ); return (0); }
lista(nn) = {for(n=2, nn, if (k = isok(n), print1(k, ", "); ); ); } \\ Michel Marcus, Nov 04 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Oct 11 2010, Oct 21 2010
EXTENSIONS
Edited by N. J. A. Sloane, Oct 14 2010
STATUS
approved