login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A360040
Prime numbers missing from A359136: prime numbers for which none of the nontrivial permutations of its digits (permitting leading zeros) produces a prime number.
1
2, 3, 5, 7, 19, 23, 29, 41, 43, 47, 53, 59, 61, 67, 83, 89, 257, 263, 269, 409, 431, 487, 523, 541, 827, 829, 853, 859, 2861, 4027, 4801, 5209, 5623, 5849
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