OFFSET
0,1
LINKS
Chai Wah Wu, Table of n, a(n) for n = 0..10000
PROG
(Python)
from __future__ import division
from sympy import isprime
def palgenrange2(m, l): # generator of odd-length palindromes of length at least m and at most 2*l
....if m == 1:
........yield 0
....for x in range(m//2+1, l+1):
........n = 10**(x-1)
........for y in range(n, n*10):
............s = str(y)
............yield int(s+s[-2::-1])
def A256048(n):
....sn = str(n)
....for p in palgenrange2(len(sn)+2, len(sn)+20):
........if sn in str(p)[1:-1] and isprime(p):
............break
....else:
........return 'search limit reached'
....return p # Chai Wah Wu, Mar 22 2015
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Felix Fröhlich, Mar 10 2015
EXTENSIONS
a(10), a(12), a(16), a(18) corrected by Chai Wah Wu, Mar 22 2015
STATUS
approved