A342216 Twin primes p such that the absolute difference of p and the reverse of its twin is a twin prime.

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

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