The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A139099 Numbers 2n+1 for which A002326(n) are record values of A002326. 3
 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 (list; graph; refs; listen; history; text; internal format)
 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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 5 19:23 EDT 2021. Contains 343573 sequences. (Running on oeis4.)