|
| |
|
|
A173286
|
|
2*prime(prime(prime(n)))-3 and 3*prime(prime(prime(n)))-2 are both primes.
|
|
1
|
|
|
|
1, 2, 5, 8, 9, 15, 26, 53, 63, 86, 92, 93, 95, 116, 137, 152, 233, 254, 281, 303, 329, 334, 352, 386, 392, 415, 423, 460, 470, 476, 508, 565, 570, 601, 660, 673, 680, 725, 748, 898, 907, 942, 948, 952, 958, 1045, 1119, 1126, 1138, 1140, 1259, 1314, 1360
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Table of n, a(n) for n=1..53.
|
|
|
EXAMPLE
|
a(1) = 1 becaise 2*p(p(p(1)))-3 = 7 = prime and 3*p(p(p(1)))-2 = 13 = prime; a(2) = 2 because 2*p(p(p(2)))-3 = 19 = prime and 3*p(p(p(2)))-2 = 31 = prime; a(3) = 5 because 2*p(p(p(5)))-3 = 379 = prime amd 3*p(p(p(5)))-2 = 251 = prime; a(4) = 8 because 2*p(p(p(8)))-3 = 991 = prime and 3*p(p(p(8)))-2 = 659 = prime; a(5) = 9 because 2*p(p(p(9)))-3 = 1291 = prime and 3*p(p(p(9)))-2 = 859 = prime; a(6) = 15 because 2*p(p(p(15)))-3 = 3889 = prime and 3*p(p(p(15)))-2 = 2591 = prime.
|
|
|
CROSSREFS
|
Cf. A038580, A063908, A088878.
Sequence in context: A032684 A026448 A050678 * A088620 A068702 A083724
Adjacent sequences: A173283 A173284 A173285 * A173287 A173288 A173289
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Juri-Stepan Gerasimov, Feb 15 2010
|
|
|
EXTENSIONS
|
Extended beyond 15 by R. J. Mathar, Mar 01 2010
|
|
|
STATUS
|
approved
|
| |
|
|
