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

1,2

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

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 *)

Crossrefs

Cf. A002326, A001122.

Sequence in context: A034936 A204657 A167791 * A152259 A219611 A003071

Adjacent sequences: A139096 A139097 A139098 * A139100 A139101 A139102

Keyword

nonn

Author

Vladimir Shevelev, Jun 05 2008

Extensions

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

Status

approved