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

1,2

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.

Links

Table of n, a(n) for n=1..24.

Example

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.

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]);

Crossrefs

Cf. A002385, A103168, A340592, A350836.

Sequence in context: A009928 A050441 A225921 * A205354 A281699 A082668

Adjacent sequences: A350847 A350848 A350849 * A350851 A350852 A350853

Keyword

nonn,base,more

Author

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

Status

approved