A352852 - OEIS

%I #14 Apr 09 2022 02:24:18

%S 2,523,701,2213,2243,3041,3701,4177,4423,6451,7673,8447,8513,9587,

%T 11131,15233,15331,15583,17519,19051,20071,20333,22483,24767,25951,

%U 26633,28183,28771,28901,30773,33461,33713,38803,39419,39989,41627,42131,43237,44633,50321,50333,51991,53551,54713,56687

%N Primes p such that, if q is the next prime, p^2 + q is a prime times a power of 10.

%C Primes prime(k) such that when any trailing zeros are removed from A352851(k), the result is prime.

%H Robert Israel, <a href="/A352852/b352852.txt">Table of n, a(n) for n = 1..10000</a>

%e a(3) = 701 is a term because it is prime, 709 is the next prime, and 701^2 + 709 = 492110 where 49211 is prime.

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

%p q:= 2:

%p while count < 100 do

%p   p:= q; q:= nextprime(p);

%p   v:= p^2+q;

%p   if v mod 10 = 0 then v:= v/10^min(padic:-ordp(v, 2), padic:-ordp(v, 5)) fi;

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

%p od:

%p R;

%t f[n_] := n/10^IntegerExponent[n, 10]; Select[Range[60000], PrimeQ[#] && PrimeQ[f[#^2 + NextPrime[#]]] &] (* _Amiram Eldar_, Apr 07 2022 *)

%Y Cf. A352837, A352851.

%K nonn

%O 1,1

%A _J. M. Bergot_ and _Robert Israel_, Apr 05 2022