|
| |
|
|
A087679
|
|
n +/- 2 are both prime.
|
|
11
| |
|
|
5, 9, 15, 21, 39, 45, 69, 81, 99, 105, 111, 129, 165, 195, 225, 231, 279, 309, 315, 351, 381, 399, 441, 459, 465, 489, 501, 615, 645, 675, 741, 759, 771, 825, 855, 861, 879, 885, 909, 939, 969, 1011, 1089, 1095, 1215, 1281, 1299, 1305, 1425, 1431, 1449, 1485
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Midpoint of cousin prime pairs.
|
|
|
LINKS
| Eric Weisstein's World of Mathematics, Cousin Primes
|
|
|
FORMULA
| a(n) = (A023200(n) + A046132(n))/2 = A023200(n) + 2 = A046132(n) - 2.
|
|
|
MAPLE
| ZL:=[]:for p from 1 to 1485 do if (isprime(p) and isprime(p+4) ) then ZL:=[op(ZL), (p+(p+4))/2]; fi; od; print(ZL); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 07 2007
|
|
|
MATHEMATICA
| lst={}; Do[If[PrimeQ[n-2]&&PrimeQ[n+2], AppendTo[lst, n]], {n, 3, 8!, 2}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Jan 14 2009]
|
|
|
CROSSREFS
| Essentially the same as A029708.
Cf. A014574, A087678-A087683, A087695-A087697, A088762.
Sequence in context: A063093 A095948 A161536 * A179187 A075343 A102176
Adjacent sequences: A087676 A087677 A087678 * A087680 A087681 A087682
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Zak Seidov (zakseidov(AT)yahoo.com), Sep 27 2003
|
|
|
EXTENSIONS
| More terms from Ray Chandler (rayjchandler(AT)sbcglobal.net), Oct 26 2003
|
| |
|
|
