A246872 Lesser of Gridgeman pairs in base 16 in increasing order: pairs of primes palindromic in base 16 which differ only in their middle digits by a difference of 1.

2, 337, 433, 1831, 2377, 3373, 3517, 104593, 209203, 229507, 236947, 244147, 253651, 332053, 337957, 341557, 350293, 361093, 376501, 477511, 486247, 488311, 489847, 497047, 592393, 633001, 639433, 744283, 745051, 766651, 885133, 894637, 906973, 911341, 914941

Offset

1,1

Links

Chai Wah Wu, Table of n, a(n) for n = 1..1000

Prime Curios!, 181

Example

433 and 449 are 2 primes which are 1B1 and 1C1 in hexadecimal notation.

Prog

(Python)
from gmpy2 import digits
from sympy import isprime
A246872 = [2]
for n in range(1, 16**4):
    s1 = digits(n, 16)
    s2 = s1[::-1]
    for m in range(15):
        p1, p2 = int(s1+digits(m, 16)+s2, 16), int(s1+digits(m+1, 16)+s2, 16)
        if isprime(p1) and isprime(p2):
            A246872.append(p1)
A246872 = sorted(A246872)

Crossrefs

Cf. A246488, A246870, A246871.

Sequence in context: A159488 A083863 A385928 * A057626 A201310 A324272

Adjacent sequences: A246869 A246870 A246871 * A246873 A246874 A246875

Keyword

nonn,base

Author

Chai Wah Wu, Sep 06 2014

Status

approved