A333207 Twin primes whose base-10 digit reversals are also twin primes.

3, 5, 7, 11, 13, 17, 31, 71, 101, 151, 181, 191, 313, 1031, 1033, 1231, 1279, 1301, 1321, 1429, 1453, 1933, 3301, 3391, 3541, 3583, 3853, 7349, 7457, 7547, 7589, 9241, 9437, 9679, 9721, 9769, 9857, 10007, 10067, 10273, 10301, 10429, 10457, 10501, 10711, 10859, 11057, 11701, 11717, 11777, 11833

Offset

1,1

Comments

Intersection of A001097 and A004086(A001097).

Links

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

Example

a(5) = 13 is in the sequence because both 13 and its reversal 31 are twin primes.

Maple

revdigs:= proc(n) local L, k;
  L:= convert(n, base, 10);
  add(L[-k]*10^(k-1), k=1..nops(L))
end proc:
Pr:= select(isprime, {seq(i, i=3..10^5, 2)}):
TL:= Pr intersect map(`-`, Pr, 2):
T:= TL union map(`+`, TL, 2):
sort(convert(select(t-> member(revdigs(t), T), T), list));

Mathematica

tpQ[p_]:=PrimeQ[IntegerReverse[p]]&&AnyTrue[p+{2, -2}, PrimeQ]; Select[ Prime[ Range[1500]], tpQ[#]&&tpQ[IntegerReverse[#]]&] (* Harvey P. Dale, Jan 16 2022 *)

Crossrefs

Cf. A004086, A001097. Includes A083840.

Sequence in context: A153601 A153602 A136187 * A328489 A130122 A288893

Adjacent sequences: A333204 A333205 A333206 * A333208 A333209 A333210

Keyword

nonn,base

Author

J. M. Bergot and Robert Israel, Mar 11 2020

Status

approved