A088290 Prime numbers in which the sum of the external digits = the sum of the internal digits.

1021, 1087, 1201, 1223, 1289, 1447, 1559, 1627, 2053, 2143, 2389, 2503, 2659, 2749, 3041, 3221, 3467, 3557, 3917, 4051, 4073, 4231, 4253, 4297, 4523, 4567, 4657, 4679, 4703, 5443, 5623, 5689, 5779, 5869, 6521, 6701, 6857, 6947, 7193, 7283, 7351, 7621

Offset: 1

Author

Amarnath Murthy, Sep 29 2003

Keywords

• base
• nonn

Examples

			1021 is a member 1+1 = 0+2 = 2..
		

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Primes in A101317.

Cf. A076167.

Programs

Maple

filter:= proc(n) local L,i;
  if not isprime(n) then return false fi;
  L:= convert(n,base,10);
  L[1] + L[-1] = add(L[i],i=2..nops(L)-1)
end proc:
select(filter, [seq(i,i=101..10^4,2)]); # Robert Israel, Oct 30 2024

Mathematica

edidQ[n_]:=Module[{idn=IntegerDigits[n]},idn[[1]]+idn[[-1]]==Total[Most[ Rest[idn]]]]; Select[Prime[Range[169,3000]],edidQ] (* Harvey P. Dale, Apr 20 2012 *)

Extensions

More terms from David Wasserman, Aug 04 2005

Offset changed by Andrew Howroyd, Sep 19 2024