

A235479


Primes whose base2 representation also is the base9 representation of a prime.


5



11, 13, 19, 41, 79, 109, 137, 151, 167, 191, 193, 199, 227, 239, 271, 307, 313, 421, 431, 433, 457, 487, 491, 521, 563, 613, 617, 659, 677, 709, 727, 757, 929, 947, 1009, 1033, 1051, 1249, 1483, 1693, 1697, 1709, 1721, 1831, 1951, 1979, 1987, 1993
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

This sequence is part of a twodimensional array of sequences, given in the LINK, based on this same idea for any two different bases b, c > 1. Sequence A235265 and A235266 are the most elementary ones in this list. Sequences A089971, A089981 and A090707 through A090721, and sequences A065720  A065727, follow the same idea with one base equal to 10.
For further motivation and crossreferences, see sequence A235265 which is the main entry for this whole family of sequences.


LINKS



EXAMPLE

11 = 1011_2 and 1011_9 = 6571 are both prime, so 11 is a term.


PROG

(PARI) is(p, b=9)=isprime(vector(#d=binary(p), i, b^(#di))*d~)&&isprime(p)


CROSSREFS

Cf. A235466 ⊂ A077723, A235266, A152079, A235475  A235478, A065720 ⊂ A036952, A065721  A065727, A089971 ⊂ A020449, A089981, A090707  A091924, A235394, A235395, A235461  A235482. See the LINK for further crossreferences.


KEYWORD

nonn,base


AUTHOR



STATUS

approved



