A350850 Members of A350836 that are not in A002385.

1, 14, 50, 194, 712, 762, 1100, 1994, 2701, 4959, 58376, 70478, 111538, 116416, 144080, 158736, 712410, 1319216, 1934075, 7709760, 10228166, 11601194, 94663994, 177930006

Offset: 1

Author

J. M. Bergot and Robert Israel, Jan 18 2022

Keywords

• nonn
• base
• more

Comments

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.

Examples

			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.
		

Crossrefs

Cf. A002385, A103168, A340592, A350836.

Programs

Maple

revdigs:= proc(n) local L, i;
  L:= convert(n, base, 10);
  add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
f:= proc(n) local L, p, i, r;
  L:= sort(map(t -> t[1]$t[2], ifactors(n)[2]));
  r:= L[1];
  for i from 2 to nops(L) do r:= r*10^(1+max(0, ilog10(L[i])))+L[i] od;
  r
end proc:
f(1):= 1:
filter:= proc(n) local r;
r:= revdigs(n);
(f(n) - r) mod n = 0 and (revdigs(n) <> n or not isprime(n))
end proc:
select(filter, [$1..10^6]);