|
|
A247280
|
|
Numbers n for which A242720(n) = prime(n)*(prime(n)+4)+3.
|
|
2
|
|
|
4, 6, 8, 19, 50, 59, 63, 65, 78, 85, 93, 112, 117, 143, 237, 254, 264, 276, 287, 303, 333, 371, 380, 425, 435, 440, 447, 459, 483, 485, 537, 612, 614, 659, 731, 851, 877, 920, 983, 994, 1025, 1080, 1096, 1182, 1358, 1380, 1468, 1476, 1481, 1582, 1628, 1690
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
prime(n)*(prime(n)+4) + 3, such that prime(n)+4 and prime(n)*(prime(n)+4)+2 are primes, is the second minimal possible value of A242720(n) after (prime(n)+1)^2 + 2, n>=3 (cf. A246824).
|
|
LINKS
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|