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A342216 Twin primes p such that the absolute difference of p and the reverse of its twin is a twin prime. 2
31, 41, 43, 59, 281, 283, 827, 829, 857, 859, 2081, 2083, 2381, 2593, 2711, 2801, 2803, 4003, 4273, 4517, 4933, 6359, 6689, 6947, 8087, 8089, 8387, 8537, 8599, 8627, 8839, 20479, 20509, 20809, 20981, 20983, 21019, 21191, 21193, 21319, 21379, 21491, 21493, 21523, 21589, 21739, 22699, 22741, 23059 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

For n = 4, 59 is a twin prime, the reverse of its twin 61 is 16, and |59 - 16| = 43 is a twin prime, so 59 is in the sequence.

MAPLE

digrev:= proc(n) local L, i;

L:= convert(n, base, 10);

add(10^(i-1)*L[-i], i=1..nops(L))

end proc:

filter:= proc(p, q) local t;

  t:= abs(p - digrev(q));

  isprime(t) and (isprime(t-2) or isprime(t+2))

end proc:

q:= 2: R:= NULL: count:= 0:

while count < 100 do

  p:= q; q:= nextprime(q);

  if q-p = 2 then

    if filter(p, q) then count:= count+1; R:= R, p fi;

    if filter(q, p) then count:= count+1; R:= R, q fi;

  fi

od:

R;

CROSSREFS

Cf. A004086, A001097.

Sequence in context: A156298 A099180 A156299 * A103490 A105320 A104822

Adjacent sequences:  A342213 A342214 A342215 * A342217 A342218 A342219

KEYWORD

nonn,base

AUTHOR

J. M. Bergot and Robert Israel, Mar 05 2021

STATUS

approved

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Last modified June 15 13:25 EDT 2021. Contains 345048 sequences. (Running on oeis4.)