A269891 - OEIS

A269891

Primes p such that both the concatenation and the sum of 2 and p are prime.

3, 11, 29, 41, 71, 137, 179, 239, 269, 281, 311, 347, 521, 617, 659, 857, 1019, 1031, 1061, 1277, 1319, 1481, 1487, 1787, 1871, 1997, 2027, 2111, 2129, 2381, 2549, 3167, 3251, 3371, 3539, 3557, 3581, 3671, 3767, 3917, 3929, 4001, 4019, 4049, 4091, 4229, 4337, 4421, 4481, 4517, 4547, 4799, 4967, 5639, 5657

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OFFSET

1,1

COMMENTS

All terms are lesser of twin primes (A001359).

LINKS

Zak Seidov, Table of n, a(n) for n = 1..3000

EXAMPLE

23 and 2+3=5 are primes, 211 and 2+11=13 are primes.

MATHEMATICA

Reap[Do[If[PrimeQ[2+(p=Prime[n])]&&PrimeQ[ToExpression["2"<>ToString[p]]], Sow[p]], {n, 10^3}]][[2, 1]]

Select[Prime@ Range@ 800, And[PrimeQ@ FromDigits[Prepend[IntegerDigits@ #, 2]], PrimeQ[# + 2]] &] (* Michael De Vlieger, Mar 07 2016 *)

PROG

(PARI) is(n)=isprime(n) && isprime(n+2) && isprime(eval(Str(2, n))) \\ Charles R Greathouse IV, Mar 07 2016

CROSSREFS

Subsequence of A001359.

Sequence in context: A335899 A018743 A077279 * A272000 A196190 A111227

Adjacent sequences: A269888 A269889 A269890 * A269892 A269893 A269894

KEYWORD

nonn,base

AUTHOR

Zak Seidov, Mar 07 2016

STATUS

approved