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”).

A349678
Primes p such that the multiplicative order of 2 modulo k is odd, where k is the largest odd divisor of p - 1.
0
2, 3, 5, 17, 29, 47, 113, 179, 197, 257, 293, 317, 383, 449, 467, 479, 509, 569, 659, 719, 797, 863, 1289, 1373, 1427, 1439, 1487, 1823, 1913, 1949, 2063, 2207, 2213, 2273, 2339, 2417, 2447, 2579, 2633, 2879, 2909, 3023, 3119, 3137, 3167, 3347, 3359, 3449, 3557
OFFSET
1,1
MATHEMATICA
Select[Range[3600], PrimeQ[#] && OddQ[MultiplicativeOrder[2, (# - 1)/2^IntegerExponent[# - 1, 2]]] &] (* Amiram Eldar, Nov 26 2021 *)
PROG
(PARI) isok(p) = isprime(p) && znorder(Mod(2, (p-1)/2^valuation(p-1, 2)))%2;
CROSSREFS
Subsequence of A348062.
Cf. A036259.
Sequence in context: A214735 A216061 A348062 * A029972 A077498 A118958
KEYWORD
nonn
AUTHOR
STATUS
approved