OFFSET
1,1
COMMENTS
Reversing the digits in base 256 is equivalent to reading a number in big-endian format using little-endian order with 8-bit words. See also A238853.
LINKS
Chai Wah Wu, Table of n, a(n) for n = 1..7110
Wikipedia, Endianness
EXAMPLE
1299647 is prime and written in base 16 is 13 d4 bf whereas bf d4 13 = 12571667 is also prime.
PROG
(Python)
from sympy import prime, isprime
def reversedigits(n, b=10): # reverse digits of n in base b
x, y = n, 0
while x >= b:
x, r = divmod(x, b)
y = b*y + r
return b*y + x
A253149_list = []
for n in range(1, 300):
p = prime(n)
if p > 255 and isprime(reversedigits(p, 256)):
A253149_list.append(p)
print(A253149_list)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Chai Wah Wu, Dec 30 2014
STATUS
approved