A059706 Smallest prime p such that p^n reversed is a prime.

2, 19, 5, 2, 2, 107, 2, 23, 131, 2, 17, 7, 71, 41, 47, 53, 2, 157, 79, 641, 47, 743, 109, 2, 19, 5, 1201, 193, 541, 47, 643, 1231, 3023, 173, 113, 5, 2, 101, 67, 71, 349, 353, 5, 53, 2, 709, 163, 677, 4337, 1327, 919, 769, 317, 23, 2, 503, 1009, 197, 167, 1663, 23, 37

Offset

1,1

Links

Table of n, a(n) for n=1..62.

Mathematica

Do[ k = 2; While[ ! PrimeQ[ k ] || ! PrimeQ[ ToExpression[ StringReverse[ ToString[ k^n ] ] ] ], k++ ]; Print[ k ], {n, 1, 100} ]
sprp[n_]:=Module[{p=2}, While[CompositeQ[IntegerReverse[p^n]], p= NextPrime[ p]]; p]; Array[sprp, 70] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 28 2019 *)

Prog

(Python)
from sympy import isprime, nextprime
def ok(p, n): return isprime(int(str(p**n)[::-1]))
def a(n):
  p = 2
  while not ok(p, n): p = nextprime(p)
  return p
print([a(n) for n in range(1, 63)]) # Michael S. Branicky, Feb 19 2021

Crossrefs

Cf. A059215.

Sequence in context: A354207 A358980 A092120 * A370387 A128361 A096481

Adjacent sequences: A059703 A059704 A059705 * A059707 A059708 A059709

Keyword

base,nonn

Author

Robert G. Wilson v, Feb 06 2001

Status

approved