|
| |
|
|
A105470
|
|
a(n)=1 if there is number of the form 6k+3 with prime(n) <= 6k+3 <= prime(n+1), otherwise 0.
|
|
0
| |
|
|
1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Except for the first pair of primes and for twin primes there is always at least one number of the form 6n+3 between two successive primes.
|
|
|
EXAMPLE
| a(3)=0 because between prime(3) and prime(4) there are no numbers of the form 6k+3;
a(4)=1 because between prime(4) and prime(5) there is one number of the form 6k+3: 9.
|
|
|
MATHEMATICA
| f[n_] := Count[Table[Mod[k, 6], {k, Prime[n], Prime[n + 1]}], 3]; Table[If[f[n] == 0, 0, 1], {n, 120}] (*Chandler*)
|
|
|
CROSSREFS
| Cf. A100810, A106002.
Sequence in context: A135528 A163805 A078387 * A087429 A093075 A104120
Adjacent sequences: A105467 A105468 A105469 * A105471 A105472 A105473
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Giovanni Teofilatto (g.teofilatto(AT)tiscalinet.it), May 02 2005
|
|
|
EXTENSIONS
| Edited by Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 17 2006
|
| |
|
|
