A180561 Primes that cannot become a different prime under any mapping of some single decimal digit <=> with some other single decimal digit.
11, 11779, 22669, 23333, 33533, 55333, 74279, 77999, 78857, 80603, 84871, 88177, 88747, 97039, 103091, 112181, 119701, 125813, 128147, 131143, 133499, 141587, 158771, 159979, 164341, 166063, 173933, 175781, 219613, 220279, 222601, 227387, 229727, 231317, 238829
Offset: 1
Links
- Michael S. Branicky, Table of n, a(n) for n = 1..10000
- Index to Primes, Primes that become a different prime under some mapping.
Programs
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Mathematica
fQ[n_] := Block[{id = IntegerDigits@n}, (MemberQ[id, s[[1]]] || MemberQ[id, s[[2]]]) && PrimeQ[ FromDigits[id /. {s[[1]] -> s[[2]], s[[2]] -> s[[1]] }] ]]; t = Union@ Flatten@ Table[s = {j, k}; Select[ Prime@ Range@ 25000, fQ], {j, 0, 8}, {k, j + 1, 9}]; Complement[ Prime@ Range@ 25000, t]
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Python
from sympy import isprime def m(s): return [s.translate({ord(c):ord(d), ord(d):ord(c)}) for c in set(s) for d in "0123456789" if d != c] def ok(n): return isprime(n) and not any(isprime(int(t)) for t in m(str(n))) print([k for k in range(10**6) if ok(k)]) # Michael S. Branicky, Oct 31 2023
Formula
Extensions
a(33) and beyond from Michael S. Branicky, Oct 31 2023