cp's OEIS Frontend

A350850 Members of A350836 that are not in A002385.

%I A350850 #8 Jan 25 2022 04:34:25
%S A350850 1,14,50,194,712,762,1100,1994,2701,4959,58376,70478,111538,116416,
%T A350850 144080,158736,712410,1319216,1934075,7709760,10228166,11601194,
%U A350850 94663994,177930006
%N A350850 Members of A350836 that are not in A002385.
%C A350850 Numbers k that are not palindromic primes, such that the concatenation of the prime factors of k with multiplicity is congruent mod k to the reverse of k.
%e A350850 a(3) = 50 is a term because A103168(50) = 5 mod 50 = 5 and A340592(50) = 255 mod 50 = 5, but 50 is not a palindromic prime.
%p A350850 revdigs:= proc(n) local L, i;
%p A350850   L:= convert(n, base, 10);
%p A350850   add(L[-i]*10^(i-1), i=1..nops(L))
%p A350850 end proc:
%p A350850 f:= proc(n) local L, p, i, r;
%p A350850   L:= sort(map(t -> t[1]$t[2], ifactors(n)[2]));
%p A350850   r:= L[1];
%p A350850   for i from 2 to nops(L) do r:= r*10^(1+max(0, ilog10(L[i])))+L[i] od;
%p A350850   r
%p A350850 end proc:
%p A350850 f(1):= 1:
%p A350850 filter:= proc(n) local r;
%p A350850 r:= revdigs(n);
%p A350850 (f(n) - r) mod n = 0 and (revdigs(n) <> n or not isprime(n))
%p A350850 end proc:
%p A350850 select(filter, [$1..10^6]);
%Y A350850 Cf. A002385, A103168, A340592, A350836.
%K A350850 nonn,base,more
%O A350850 1,2
%A A350850 _J. M. Bergot_ and _Robert Israel_, Jan 18 2022