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A088290
Prime numbers in which the sum of the external digits = the sum of the internal digits.
1
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
1,1
LINKS
EXAMPLE
1021 is a member 1+1 = 0+2 = 2..
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 *)
CROSSREFS
Primes in A101317.
Cf. A076167.
Sequence in context: A228625 A356947 A214732 * A209620 A179032 A179033
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Sep 29 2003
EXTENSIONS
More terms from David Wasserman, Aug 04 2005
Offset changed by Andrew Howroyd, Sep 19 2024
STATUS
approved