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A235266 Primes whose base 2 representation is also the base 3 representation of a prime. 69
2, 7, 11, 13, 41, 47, 67, 73, 79, 109, 127, 151, 173, 181, 191, 193, 211, 223, 227, 229, 233, 251, 283, 331, 367, 421, 443, 487, 541, 557, 563, 587, 601, 607, 631, 641, 661, 677, 719, 733, 877, 941, 947, 967, 971, 1033, 1187, 1193, 1201, 1301, 1321, 1373, 1447, 1451, 1471, 1531, 1567, 1571, 1657, 1667, 1669, 1697, 1709, 1759 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..64.

M. F. Hasler, Primes whose base c expansion is also the base b expansion of a prime

FORMULA

a(n) is the number whose base-3 representation is the base-2 representation of A235265(n).

PROG

(PARI) is(p, b=3, c=2)=isprime(vector(#d=digits(p, c), i, b^(#d-i))*d~)&&isprime(p) \\ This code can be used for other bases b, c when b>c. See A235265 for code valid for b<c.

CROSSREFS

Cf. A090707 - A091924, A235461 - A235482. See the LINK for further cross-references.

Sequence in context: A117048 A040128 A209630 * A140548 A243630 A287107

Adjacent sequences:  A235263 A235264 A235265 * A235267 A235268 A235269

KEYWORD

nonn,base

AUTHOR

M. F. Hasler, Jan 05 2014

STATUS

approved

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Last modified August 18 04:40 EDT 2017. Contains 290684 sequences.