|
| |
|
|
A098429
|
|
Number of cousin prime pairs (p, p+4) with p <= n.
|
|
4
|
|
|
|
0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,7
|
|
|
COMMENTS
|
Convention: a prime pair is <= n iff its smallest member is <= n.
Except for (3, 7), there is only 1 pair congruence class for cousin primes, i.e. (+1, -1) (mod 6). [From Daniel Forgues, Aug 05 2009]
|
|
|
LINKS
|
Daniel Forgues, Table of n, a(n) for n=1..99996
Eric Weisstein's World of Mathematics, Cousin Primes
|
|
|
EXAMPLE
|
First cousin prime pairs: (3,7),(7,11),(13,17),(19,23), ...
therefore the sequence starts: 0 0 1 1 1 1 2 2 2 2 2 2 3 ...
|
|
|
CROSSREFS
|
Cf. A023200, A046132, A098428, A071538.
Sequence in context: A132085 A111654 A067099 * A132090 A071538 A138194
Adjacent sequences: A098426 A098427 A098428 * A098430 A098431 A098432
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Reinhard Zumkeller, Sep 07 2004
|
|
|
EXTENSIONS
|
Edited by Daniel Forgues, Aug 01 2009
|
|
|
STATUS
|
approved
|
| |
|
|
