| 1, 2, 3, 5, 6, 8, 9, 11, 14, 15, 18, 20, 21, 23, 26, 29, 30, 33, 35, 36, 39, 41, 44, 48, 50, 51, 53, 54, 56, 63, 65, 68, 69, 74, 75, 78, 81, 83, 86, 89, 90, 95, 96, 98, 99, 105, 111, 113, 114, 116, 119, 120, 125, 128, 131, 134, 135, 138, 140, 141, 146, 153, 155, 156, 158
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
The sequence properly contains A005097. 170 is the first number which is not in A005097. One can prove that A002326(2^(2t-1))=4t. Thus if n=2^(2t-1), where, for any m>0, t=2^(m-1) then 2n is a multiple of A002326(n) while 2n+1 is a Fermat number which, as well known,is not always a prime.
|
|
FORMULA
|
The sequence is the union of A005097 and (A001567(n)-1)/2). [Conjectured by Vladimir Shevelev, proved by Ray Chandler May 26 2008]
|
|
CROSSREFS
|
Cf. A002326, A005097, A001262, A137576.
Adjacent sequences: A139788 A139789 A139790 this_sequence A139792 A139793 A139794
Sequence in context: A102781 A005097 A111332 this_sequence A027563 A000534 A136112
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Vladimir Shevelev (shevelev(AT)bgu.ac.il), May 21 2008, May 24 2008
|
|
