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A281227 Primes whose binary reflected Gray code representation is also the decimal representation of a prime. 2
2, 53, 233, 281, 397, 521, 613, 673, 733, 773, 797, 829, 1049, 1129, 1433, 1553, 1697, 1933, 2129, 2237, 2273, 2281, 2437, 2521, 2557, 2617, 2729, 2969, 3121, 3181, 3413, 3457, 3517, 3637, 3709, 3761, 3881, 4337, 4357, 4729, 4733, 4877, 4889, 5101, 5657, 5813, 5857, 6113, 6133 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Indranil Ghosh, Table of n, a(n) for n = 1..481

EXAMPLE

521 is in the sequence because 521_10 = 1100001101_2 and both 521 and 1100001101 are prime numbers in base 10.

PROG

(Python)

from sympy import isprime

def gray(n):

....return bin(n^(n/2))[2:]

i=1

j=1

while j<=481:

....if isprime(i)==True and isprime(int(gray(i)))==True:

........print str(j)+" "+str(i)

........j+=1

....i+=1

CROSSREFS

Cf. A014550, A065720, A065721, A065722, A065723, A065724.

Sequence in context: A248994 A212242 A123005 * A142477 A119112 A109791

Adjacent sequences:  A281224 A281225 A281226 * A281228 A281229 A281230

KEYWORD

nonn,base

AUTHOR

Indranil Ghosh, Jan 18 2017

STATUS

approved

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Last modified January 22 19:47 EST 2020. Contains 331153 sequences. (Running on oeis4.)