A139099 Numbers 2n+1 for which A002326(n) are record values of A002326.

1, 3, 5, 9, 11, 13, 19, 25, 29, 37, 53, 59, 61, 67, 83, 101, 107, 121, 131, 139, 149, 163, 173, 179, 181, 197, 211, 227, 269, 293, 317, 347, 349, 373, 379, 389, 419, 421, 443, 461, 467, 491, 509, 523, 541, 547, 557, 563, 587, 613, 619, 653, 659, 661, 677, 701

Offset: 1

Author

Vladimir Shevelev, Jun 05 2008

Keywords

• nonn

Comments

Question: does this sequence contain infinitely many composite numbers?

Nonprimes in the sequence are 1, 9, 25, 121, 1369,... (no more up to at least 100000). [R. J. Mathar, Jul 14 2010]

Links

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

Crossrefs

Cf. A002326, A001122.

Programs

Mathematica

a[n_] := MultiplicativeOrder[2, 2 n + 1]; s = {}; am = 0; Do[a1 = a[n]; If[a1 > am, am = a1; AppendTo[s, 2 n + 1]], {n, 0, 360}]; s (* Amiram Eldar, Sep 12 2019 *)

Extensions

More terms from R. J. Mathar, Jul 14 2010