A281382 Numbers n such that the decimal equivalent of the binary reflected Gray code representation of n is a palindromic prime.

2, 3, 5, 6, 13, 70, 213, 217, 229, 253, 422, 426, 446, 465, 534, 541, 705, 741, 857, 869, 8441, 8481, 9190, 9221, 9293, 10210, 10349, 10453, 10929, 11049, 12006, 12281, 12329, 12721, 12793, 14109, 14282, 20578, 20934, 21009, 21629, 21701, 22810, 22866, 23221, 23421, 28705, 29397

Offset

1,1

Comments

Numbers n such that A003188(n) is both prime and palindromic.

Links

Indranil Ghosh and Chai Wah Wu, Table of n, a(n) for n = 1..13824, first 1281 terms from Indranil Ghosh.

Example

213 is in the sequence because A003188(213) = 191 and 191 is a palindromic prime.

Mathematica

Select[Range@ 30000, And[PrimeQ@ #, Reverse@ # == # &@ IntegerDigits@ #] &@ BitXor[#, Floor[#/2]] &] (* Michael De Vlieger, Mar 30 2017 *)

Prog

(Python)
from sympy import isprime
def G(n):
....return int(bin(n^(n/2))[2:], 2)
i=0
j=1
while j<=1281:
....if G(i)==int(str(G(i))[::-1]) and isprime(G(i))==True:
........print str(j)+" "+str(i)
........j+=1
....i+=1

Crossrefs

Cf. A002385, A003188.

Sequence in context: A075371 A218948 A057704 * A078203 A285937 A253647

Adjacent sequences: A281379 A281380 A281381 * A281383 A281384 A281385

Keyword

nonn,base

Author

Indranil Ghosh, Jan 21 2017

Status

approved