|
| |
|
|
A056206
|
|
Smallest prime p such that p+2^n is also a prime.
|
|
9
| |
|
|
3, 3, 3, 3, 5, 3, 3, 7, 11, 7, 5, 3, 17, 37, 3, 3, 29, 3, 53, 7, 17, 67, 11, 43, 41, 97, 29, 3, 11, 3, 11, 61, 17, 79, 53, 31, 29, 7, 23, 97, 71, 277, 29, 7, 59, 127, 5, 61, 191, 193, 101, 37, 5, 163, 3, 97, 131, 577, 131, 151, 197, 193, 29, 13, 131, 709, 3, 61, 29, 67, 11, 331
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,1
|
|
|
FORMULA
| a(n)=Min{p|p+2^n=q, both p and q are primes}
|
|
|
EXAMPLE
| n=9, 512+{2,3,5,7,11,...}={514,515,519,523,...}={2.257,5.103,11.47,3.173,523=prime,...}. The smallest suitable prime is 11 and it gives 523=512+11. So a(9)=11.
|
|
|
CROSSREFS
| Cf. A056208.
Sequence in context: A046074 A068048 A176994 * A125713 A162220 A118911
Adjacent sequences: A056203 A056204 A056205 * A056207 A056208 A056209
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Labos E. (labos(AT)ana.sote.hu), Oct 06 2000
|
| |
|
|
