cp's OEIS Frontend

A333327 Primes p such that, if p = Sum_{0<=i<=k} d_i*10^i is the decimal expansion, p mod (d_i*10^i) is prime for 0<=i<=k.

%I A333327 #12 Mar 15 2020 22:44:58
%S A333327 17,23,37,47,53,83,113,317,353,367,397,443,467,479,647,653,683,743,
%T A333327 773,953,983,997,1223,1283,1367,1373,1433,1523,1823,1997,2137,2467,
%U A333327 2677,2887,3167,3389,3617,3727,3967,4283,4349,4523,4643,5197,5827,5839,5857,6113,6173,6317,6337,6353,6653,6863
%N A333327 Primes p such that, if p = Sum_{0<=i<=k} d_i*10^i is the decimal expansion, p mod (d_i*10^i) is prime for 0<=i<=k.
%C A333327 No digits are 0.  Last digit is not 1.
%H A333327 Robert Israel, <a href="/A333327/b333327.txt">Table of n, a(n) for n = 1..1000</a>
%e A333327 a(7) = 113 is a term because 113, 113 mod 100 = 13, 113 mod 10 = 3, and 113 mod 3 = 2 are all prime.
%p A333327 filter:= proc(p) local L;
%p A333327   if not isprime(p) then return false fi;
%p A333327   L:= convert(p,base,10);
%p A333327   if has(0,L) then return false fi;
%p A333327   andmap(i -> isprime(p mod (L[i]*10^(i-1))), [$1..nops(L)])
%p A333327 end proc:
%p A333327 select(filter, [seq(i,i=13..10000,2)]);
%Y A333327 Contained in A227916.
%K A333327 nonn,base
%O A333327 1,1
%A A333327 _J. M. Bergot_ and _Robert Israel_, Mar 15 2020