|
| |
|
|
A091666
|
|
Least k such that prime(n)^2 + k is prime.
|
|
7
| |
|
|
1, 2, 4, 4, 6, 4, 4, 6, 12, 12, 6, 4, 12, 12, 4, 10, 10, 6, 4, 10, 4, 6, 10, 6, 4, 10, 4, 18, 6, 12, 10, 6, 4, 12, 28, 6, 10, 4, 4, 18, 10, 10, 12, 4, 12, 6, 10, 10, 10, 12, 4, 10, 18, 28, 18, 22, 6, 12, 4, 16, 18, 4, 4, 10, 4, 4
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Conjecturally, a(n) << log^2 n (with constant around 8/e^gamma in the supremum). [Charles R Greathouse IV, Dec 27 2011]
|
|
|
EXAMPLE
| prime(3)=5, 5*5=25 for k=4 25+4=29 prime, k=4 is the least k with prime(3)^2 + k prime
|
|
|
CROSSREFS
| Cf. A001248, A062772, A054271, A133517, A133518, A133519, A133520, A133521, A133522, A001223.
Sequence in context: A160904 A205969 A049782 * A084290 A062011 A132857
Adjacent sequences: A091663 A091664 A091665 * A091667 A091668 A091669
|
|
|
KEYWORD
| base,easy,nonn
|
|
|
AUTHOR
| Pierre CAMI (colettecami(AT)aol.com), Jan 27 2004
|
| |
|
|
