A281047 - OEIS

%I #26 Jul 28 2020 19:17:57

%S 483,525,635,2015,2043,3335,3575,4275,10317,14955,17855,22547,49433,

%T 51695,52773,79877,125807,132725,176417,242073,314177,451937,463517,

%U 590663,598793,707817,795143,798335,963815,994565,1095465

%N Numbers n such that abs(n - 4^k) is prime for k = 1..8.

%H Charles R Greathouse IV, <a href="/A281047/b281047.txt">Table of n, a(n) for n = 1..10000</a>

%H José Camacho Medina, <a href="http://matematicofresnillense.blogspot.mx/2016/08/cadenas-de-numeros-primos.html">Cadenas de Numeros Primos</a> (in Spanish).

%F a(n) >> n log^8 n. - _Charles R Greathouse IV_, Jan 13 2017

%e For n = 483, the primes are {479, 467, 419, 227, 541, 3613, 15901, 65053}.

%t Select[Range[11*10^5],AllTrue[Abs[#-4^Range[8]],PrimeQ]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 28 2020 *)

%o (PARI) is(n)=for(k=1,8,if(!isprime(abs(n-4^k)), return(0))); 1 \\ _Charles R Greathouse IV_, Jan 13 2017

%K nonn

%O 1,1

%A _José de Jesús Camacho Medina_, Jan 13 2017

%E More terms from _Charles R Greathouse IV_, Jan 13 2017