A179538 Numbers 2n+1 for which A003558(n), n>=1, are record values of A003558.

3, 5, 7, 11, 13, 19, 23, 29, 37, 47, 53, 59, 61, 67, 71, 79, 83, 101, 103, 107, 121, 131, 139, 149, 163, 167, 173, 179, 181, 191, 197, 199, 211, 227, 239, 263, 269, 271, 293, 311, 317, 347, 349, 359, 367, 373, 379, 383, 389, 419, 421, 443, 461, 463, 467, 479

Offset: 1

Author

Vladimir Shevelev, Jul 18 2010

Keywords

• nonn

Comments

Conjecture. All terms are primes except for a finite set of squares of primes.

All terms from a(1) to a(5000) are primes except for a(21) = 121 = 11^2, supporting V. Shevelev's conjecture. [John W. Layman, Jul 22 2010]

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A003558, A139099, A179383, A179481.

Programs

Mathematica

s = {}; am = 0; Do[a = Min[MultiplicativeOrder[2, n, {-1, 1}]]; If[a > am, am = a; AppendTo[s, n]], {n, 3, 480, 2}]; s (* Amiram Eldar, Sep 13 2019 *)

Extensions

a(31)-a(56) from John W. Layman, Jul 22 2010