|
| |
|
|
A088631
|
|
Largest number m < n such that m+n is a prime.
|
|
5
|
|
|
|
1, 2, 3, 2, 5, 6, 5, 8, 9, 8, 11, 10, 9, 14, 15, 14, 13, 18, 17, 20, 21, 20, 23, 22, 21, 26, 25, 24, 29, 30, 29, 28, 33, 32, 35, 36, 35, 34, 39, 38, 41, 40, 39, 44, 43, 42, 41, 48, 47, 50, 51, 50, 53, 54, 53, 56, 55, 54, 53, 52, 51, 50, 63, 62, 65, 64, 63, 68, 69, 68, 67, 66, 65, 74, 75
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
2,2
|
|
|
REFERENCES
|
F. W. Roush and D. G. Rogers, A prime algorithm?, preprint, 1999.
|
|
|
LINKS
|
Table of n, a(n) for n=2..76.
|
|
|
FORMULA
|
a(n) = p-n where p = largest prime <= 2n-1.
|
|
|
EXAMPLE
|
Adding 1,2,3,2,5 to 2,3,4,5,6 we get the primes 3,5,7,7,11.
|
|
|
MAPLE
|
with(numtheory); A088631 := n->prevprime(2*n)-n;
|
|
|
CROSSREFS
|
Cf. A088633. Second column of A088643.
Sequence in context: A218613 A164912 A088861 * A086184 A056552 A049273
Adjacent sequences: A088628 A088629 A088630 * A088632 A088633 A088634
|
|
|
KEYWORD
|
easy,nonn
|
|
|
AUTHOR
|
N. J. A. Sloane, Nov 24 2003
|
|
|
STATUS
|
approved
|
| |
|
|
