This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
from sympy import isprime
from itertools import count, islice, product
def t(s): return s.translate({ord("2"):ord("5"), ord("5"):ord("2")})
def a(n):
if n < 2: return 0
c = 0
for mid in product("01258", repeat=n-2):
s = "1" + "".join(mid) + "1"
ss = set([s, s[::-1], t(s), t(s[::-1])])
if len(ss) != 4: continue
if all(isprime(int(w)) for w in ss): c += 1
return c
print([a(n) for n in range(1, 11)]) # Michael S. Branicky, Apr 27 2024