Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #17 Jul 29 2019 11:52:33
%S 5,13,17,97,257,401,769,1153,3041,14177,65537,286721,1810433,2752513,
%T 4043777,7340033,13631489,23068673,72222721,319291393,348061697,
%U 625483777,3937533953,54498164737,106216554497,121899667073,151597350913,342456532993
%N Sorted list of prime factors of numbers of the form 3^(2^m) + 2^(2^m) with m >= 0.
%C Primes p such that the multiplicative order of 3/2 (mod p) is a power of 2.
%H Arkadiusz Wesolowski, <a href="/A294132/b294132.txt">Table of n, a(n) for n = 1..48</a>
%H 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 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 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.
%e The first 5 such numbers are 5, 13, 97, 6817, 43112257, 1853024483819137. Their prime factorizations are (5), (13), (97), (17) (401), (14177) (3041), (1153) (1607133116929). - _N. J. A. Sloane_, Oct 29 2017
%o (PARI) print1(5, ", "); forprime(p=13, 342456532993, z=znorder(Mod(3/2, p)); if(2^ispower(z)==z, print1(p, ", ")));
%Y Cf. A050244, A094499, A082101, A294133, A294134, A294135, A294136.
%K nonn
%O 1,1
%A _Arkadiusz Wesolowski_, Oct 23 2017