A262833 (7,2)-primes (defined in Comments).

2, 3, 5, 7, 17, 31, 43, 47, 61, 71, 73, 89, 101, 103, 113, 127, 157, 173, 197, 199, 229, 239, 241, 269, 271, 281, 311, 337, 353, 367, 379, 383, 397, 409, 439, 449, 463, 479, 509, 521, 577, 607, 617, 631, 647, 661, 673, 677, 719, 743, 761, 827, 857, 887, 911

Offset

1,1

Comments

Let V = (b(1), b(2), ..., b(k)), where k > 1 and b(i) are distinct integers > 1 for j = 1..k. Call p a V-prime if the digits of p in base b(1) spell a prime in each of the bases b(2), ..., b(k).

Links

Clark Kimberling, Table of n, a(n) for n = 1..10000

Mathematica

{b1, b2} = {2, 7};
u = Select[Prime[Range[6000]], PrimeQ[FromDigits[IntegerDigits[#, b1], b2]] &]; (* A235477 *)
v = Select[Prime[Range[6000]], PrimeQ[FromDigits[IntegerDigits[#, b2], b1]] &]; (* A262833 *)
w = Intersection[u, v]; (* A262834 *)
(* Peter J. C. Moses, Sep 27 2015 *)

Crossrefs

Cf. A000040, A262729, A262832, A262834.

Sequence in context: A030480 A048418 A074788 * A070805 A255161 A103385

Adjacent sequences: A262830 A262831 A262832 * A262834 A262835 A262836

Keyword

nonn,easy,base

Author

Clark Kimberling, Nov 01 2015

Status

approved