A318568 Primes p such that 2^p reversed is a prime.

5, 7, 17, 37, 107, 137, 271

Offset

1,1

Comments

Equivalently, primes in A057708. - Muniru A Asiru, Dec 25 2018

a(8) > 200000 using A057708. - Michael S. Branicky, May 17 2025

Links

Table of n, a(n) for n=1..7.

Mathematica

Select[Prime[Range[100]], PrimeQ[ToExpression[StringReverse[ToString[2^#]]]] &]

Prog

(Magma) [p: p in PrimesUpTo(200) | IsPrime(Seqint(Reverse(Intseq(2^p))))];
(PARI) isok(p) = isprime(p) && isprime(fromdigits(Vecrev(digits(2^p)))); \\ Michel Marcus, Sep 22 2018
(GAP) P0:=List(List([1..300], j->Reversed(ListOfDigits(2^j))), k->Sum([1..Size(k)], i->k[i]*10^(Size(k)-i)));;
a:=Filtered([1..Length(P0)], m->IsPrime(m) and IsPrime(P0[m]));; Print(a); # Muniru A Asiru, Dec 25 2018

Crossrefs

Cf. A059706.

Subsequence of A057708.

Sequence in context: A018538 A038968 A243400 * A239414 A163570 A113282

Adjacent sequences: A318565 A318566 A318567 * A318569 A318570 A318571

Keyword

nonn,base,more

Author

Vincenzo Librandi, Sep 22 2018

Status

approved