cp's OEIS Frontend

A294134 Sorted list of prime factors of numbers of the form 7^(2^m) + 2^(2^m) with m >= 0.

%I A294134 #12 Nov 02 2017 15:39:16
%S A294134 3,17,53,97,257,449,2417,7681,8513,65537,89633,114689,339121,876097,
%T A294134 1321729,1454081,2572289,4638721,5463041,7340033,27688961,47047681,
%U A294134 62177153,93847553,113418241,374734849,3731619841,13037142017,13555990529,13951408129,142807662593
%N A294134 Sorted list of prime factors of numbers of the form 7^(2^m) + 2^(2^m) with m >= 0.
%C A294134 Primes p other than 5 such that the multiplicative order of 7/2 (mod p) is a power of 2.
%H A294134 Arkadiusz Wesolowski, <a href="/A294134/b294134.txt">Table of n, a(n) for n = 1..43</a>
%H A294134 Anders Björn and Hans Riesel, <a href="http://dx.doi.org/10.1090/S0025-5718-98-00891-6">Factors of generalized Fermat numbers</a>, Math. Comp. 67 (1998), no. 221, pp. 441-446.
%H A294134 Anders Björn and Hans Riesel, <a href="http://dx.doi.org/10.1090/S0025-5718-05-01816-8">Table errata to “Factors of generalized Fermat numbers”</a>, Math. Comp. 74 (2005), no. 252, p. 2099.
%H A294134 Anders Björn and Hans Riesel, <a href="http://dx.doi.org/10.1090/S0025-5718-10-02371-9">Table errata 2 to "Factors of generalized Fermat numbers"</a>, Math. Comp. 80 (2011), pp. 1865-1866.
%o A294134 (PARI) print1(3, ", "); forprime(p=17, 142807662593, z=znorder(Mod(7/2, p)); if(2^ispower(z)==z, print1(p, ", ")));
%Y A294134 Cf. A176946, A294132, A294133, A294135, A294136.
%K A294134 nonn
%O A294134 1,1
%A A294134 _Arkadiusz Wesolowski_, Oct 23 2017