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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,changed

AUTHOR

Vladimir Shevelev, Jun 05 2008

EXTENSIONS

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

STATUS

approved

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Last modified September 21 09:15 EDT 2019. Contains 327253 sequences. (Running on oeis4.)