|
Search: id:A047389
|
|
|
| A047389 |
|
Numbers that are congruent to {3, 5} mod 7. |
|
+0
1
|
|
| 3, 5, 10, 12, 17, 19, 24, 26, 31, 33, 38, 40, 45, 47, 52, 54, 59, 61, 66, 68, 73, 75, 80, 82, 87, 89, 94, 96, 101, 103, 108, 110, 115, 117, 122, 124, 129, 131, 136, 138, 143, 145, 150, 152, 157, 159, 164, 166, 171
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Primitive roots of 7. The first differences are periodic: 2,5,2,5,2,5.... - Paolo P. Lava (ppl(AT)spl.at), Feb 29 2008
|
|
FORMULA
|
a(n)=-4+(1/2)*Sum_{k=0..n}{7-3*(-1)^n}, with n>=1 - Paolo P. Lava (ppl(AT)spl.at), Feb 29 2008
a(n)=7*n-a(n-1)-6 (with a(1)=3) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 24 2009]
|
|
EXAMPLE
|
For n=2, a(2)=7*2-3-6=5; n=3, a(3)=7*3-5-6=10; n=4, a(4)=7*4-10-6=12 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 24 2009]
|
|
MAPLE
|
P:=proc(n, m) local a, i, ok; for i from 1 by 1 to n do if (i^(m-1) mod m)=1 then a:=1; ok:=1; while a<m-1 do if (i^a mod m)=1 then ok:=0; fi; a:=a+1; od; if ok=1 then print(i); fi; fi; od; end: P(100, 7); - Paolo P. Lava (ppl(AT)spl.at), Feb 29 2008
|
|
CROSSREFS
|
Sequence in context: A067230 A075741 A119133 this_sequence A093661 A080561 A007557
Adjacent sequences: A047386 A047387 A047388 this_sequence A047390 A047391 A047392
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com).
|
|
|
Search completed in 0.002 seconds
|
