A358087 - OEIS

A358087

Primes that can be written as 2^x - p where p is a prime and x is a multiple of p.

%I #12 Nov 10 2022 07:44:09

%S 2,5,61,509,1019,4093,8179,524269,1048571,16777213,

%T 2596148429267413814265248164610011,

%U 1361129467683753853853498429727072845819,1427247692705959881058285969449495136382746619,1427247692705959881058285969449495136382746621,45671926166590716193865151022383844364247891937

%N Primes that can be written as 2^x - p where p is a prime and x is a multiple of p.

%H Robert Israel, <a href="/A358087/b358087.txt">Table of n, a(n) for n = 1..29</a>

%e a(3) = 61 is a term because 61 = 2^6 - 3 where 61 and 3 are prime and 6 is divisible by 3.

%p R:= NULL: count:= 0:

%p for k from 1 while count < 20 do

%p P:= sort(convert(numtheory:-factorset(k),list),`>`);

%p for p in P do

%p x:= 2^k-p;

%p if isprime(x) then R:= R,x; count:= count+1; fi

%p od od:

%p R;

%Y Contains A057678.

%Y Cf. A358079.

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Oct 30 2022