OFFSET
1,1
LINKS
Donovan Johnson, 1384 terms > a(9)
EXAMPLE
a(1) = 74431 = 7^4 * 31 because 6 and 30 divide 74430 and 8 and 32 divide 74432.
MATHEMATICA
Do[ f = Transpose[ FactorInteger[n]][[1]]; If[ Length[f] > 1 && Union[ Mod[n - 1, f - 1]] == {0} && Union[ Mod[n + 1, f + 1]] == {0}, Print[n]], {n, 6, 10^10}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Don Reble, Jan 22 2003
EXTENSIONS
a(6)-a(7) from Donovan Johnson, Apr 09 2010
a(8)-a(9) from Donovan Johnson, Jan 21 2013
STATUS
approved