%I #11 Apr 03 2023 10:36:13

%S 2,337,433,1831,2377,3373,3517,104593,209203,229507,236947,244147,

%T 253651,332053,337957,341557,350293,361093,376501,477511,486247,

%U 488311,489847,497047,592393,633001,639433,744283,745051,766651,885133,894637,906973,911341,914941

%N 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.

%H Chai Wah Wu, <a href="/A246872/b246872.txt">Table of n, a(n) for n = 1..1000</a>

%H Prime Curios!, <a href="https://t5k.org/curios/cpage/8733.html">181</a>

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

%o (Python)

%o from gmpy2 import digits

%o from sympy import isprime

%o A246872 = [2]

%o for n in range(1,16**4):

%o ....s1 = digits(n,16)

%o ....s2 = s1[::-1]

%o ....for m in range(15):

%o ........p1, p2 = int(s1+digits(m,16)+s2,16), int(s1+digits(m+1,16)+s2,16)

%o ........if isprime(p1) and isprime(p2):

%o ............A246872.append(p1)

%o A246872 = sorted(A246872)

%Y Cf. A246488, A246870, A246871.

%K nonn,base

%O 1,1

%A _Chai Wah Wu_, Sep 06 2014