OFFSET
1,1
COMMENTS
Any prime number p >= 10^11 has necessarily a duplicate digit, say that appears at positions i and j. Applying the nontrivial permutation (i j) to the digits of p yields a prime number (p itself), hence p does not belong to the sequence and the sequence is finite.
All terms belong to A360041.
FORMULA
The nontrivial permutations of the digits of 409 (permitting leading zeros) are:
049 = 7^2,
094 = 2 * 47,
490 = 2 * 5 * 7^2,
904 = 2^3 * 113,
940 = 2^2 * 5 * 47,
so 409 belongs to the sequence.
PROG
(PARI) is(p) = { my (d=digits(p)); if (#d > #Set(d), return (0), forperm (vecsort(d), t, my (q=fromdigits(Vec(t))); if (p!=q && isprime(q), return (0))); return (1)) }
CROSSREFS
KEYWORD
nonn,base,fini,full
AUTHOR
Rémy Sigrist, Jan 23 2023
STATUS
approved