A242276 - OEIS

%I #24 Aug 21 2014 21:20:13

%S 11,31,3,11,17,3,5,43,5,13,17,19,73,7,13,19,3,5,127,23,89,5,17,29,37,

%T 73,7,13,31,29,113,37,109,17,257,3,31,47,31,151,43,127,7,23,41,73,109,

%U 53,157,3,11,257,7,19,67,31,331,5,29,73,5,7,17,19,3,17,251,7,13,151,59,233,11,31,41,43,337,23,683,7,31,73,5,13

%N Irregular array of factors of n-th Poulet number read by rows, where row n corresponds to A001567(n).

%H Felix Fröhlich, <a href="/A242276/b242276.txt">Table of n, a(n) for n = 1..2165</a> (all terms up to 10^7)

%e The first three Poulet numbers (2-pseudoprimes) are 341 = 11*31, 561 = 3*11*17, and 645 = 3*5*43, so the sequence begins:

%e 11, 31;

%e 3, 11, 17;

%e 3, 5, 43;

%e etc.

%o (PARI) forcomposite(n=1, 1e4, if(Mod(2, n)^(n-1)==1, f=factor(n)[, 1]; for(i=1, #f, print1(f[i], ", "))))

%Y Cf. A001567, A007011, A084653, A084654, A084655.

%K nonn,tabf

%O 1,1

%A _Felix Fröhlich_, Aug 16 2014