login
This site is supported by donations to The OEIS Foundation.

 

Logo

Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A179676 Numbers m=2*n-1 for all n>2 not in A179460. 1
7, 15, 21, 23, 31, 35, 39, 45, 47, 49, 51, 55, 63, 71, 73, 75, 79, 85, 87, 89, 91, 93, 95, 103, 105, 111, 115, 117, 119, 123, 127, 133, 135, 143, 147, 151, 153, 155, 159, 161, 165, 167, 175, 183, 187, 189, 191, 195, 199, 215, 217, 219, 221, 223, 225, 231, 233, 235, 237, 239, 245, 247, 253, 255, 259 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Consider the algorithm of calculation ord_(2n-1)(2) in A179680, and the average of the 2-adic orders l_1, ..., l_k defined there. For terms of the sequence it is more than 2, while for other odd numbers(>=3), it equals 2. This means that only for the terms of the sequence the number of odd residues in {1,2,...,2^ord_(2*n-1)(2)} (considered in the reduced residue system modulo 2*n-1)less than even ones.

LINKS

Table of n, a(n) for n=1..65.

CROSSREFS

Cf. A179460, A007814, A002326

Sequence in context: A214467 A151971 A014659 * A053354 A022552 A082658

Adjacent sequences:  A179673 A179674 A179675 * A179677 A179678 A179679

KEYWORD

nonn,uned

AUTHOR

Vladimir Shevelev, Jul 24 2010

STATUS

approved

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

Content is available under The OEIS End-User License Agreement .

Last modified July 29 04:40 EDT 2014. Contains 245018 sequences.