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A333207 Twin primes whose base-10 digit reversals are also twin primes. 1
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 (list; graph; refs; listen; history; text; internal format)
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));

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

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Last modified August 8 11:31 EDT 2020. Contains 336298 sequences. (Running on oeis4.)