A269326 - OEIS

A269326

Let k be a number which is simultaneously Sierpiński and Riesel, and let P be a set of primes which cover every number of the form k*2^m + 1 and of the form k*2^m - 1 with m >= 1. Sequence shows elements of the set P which has the property that the product of its primes is as small as it is possible.

%I #18 Sep 08 2022 08:46:15

%S 3,5,7,11,13,17,19,31,37,41,61,73,97,109,151,241,257,331

%N Let k be a number which is simultaneously Sierpiński and Riesel, and let P be a set of primes which cover every number of the form k*2^m + 1 and of the form k*2^m - 1 with m >= 1. Sequence shows elements of the set P which has the property that the product of its primes is as small as it is possible.

%H Fred Cohen and J. L. Selfridge, <a href="http://dx.doi.org/10.1090/S0025-5718-1975-0376583-0">Not every number is the sum or difference of two prime powers</a>, Math. Comput. 29 (1975), pp. 79-81.

%o (Magma) PrimeDivisors((2^36-1)*(2^48-1)*(2^60-1))[1..18];

%Y Cf. A076335, A076336, A101036.

%K nonn,fini,full

%O 1,1

%A _Arkadiusz Wesolowski_, Feb 23 2016