|
Search: id:A066049
|
|
|
| A066049 |
|
Numbers n such that 2*n^2 - 1 is a prime. |
|
+0
17
|
|
| 2, 3, 4, 6, 7, 8, 10, 11, 13, 15, 17, 18, 21, 22, 24, 25, 28, 34, 36, 38, 39, 41, 42, 43, 45, 46, 49, 50, 52, 56, 59, 62, 63, 64, 69, 73, 76, 80, 81, 85, 87, 91, 92, 95, 98, 102, 108, 109, 112, 113, 115, 118, 125, 126, 127, 132, 134, 137, 140, 141, 143, 153, 154, 155
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
It is conjectured that this sequence is infinite.
A066436 gives resulting primes p such that (p+1)/2 is square. - Chandler
a(n) = A160697(n+1). [From Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), May 24 2009]
|
|
REFERENCES
|
D. Shanks, Solved and Unsolved Problems in Number Theory, 2nd. ed., Chelsea, 1978, p. 31.
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=1..1000
|
|
FORMULA
|
a(n) = A090697(n)/2 = A110558(n)/4. - Chandler
|
|
PROGRAM
|
(PARI) { n=0; for (m=1, 10^9, if (isprime(2*m^2 - 1), write("b066049.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 08 2009]
|
|
CROSSREFS
|
Cf. A028870, A066436, A090697, A091176, A110558.
Sequence in context: A099619 A027564 A161907 this_sequence A160697 A131629 A167701
Adjacent sequences: A066046 A066047 A066048 this_sequence A066050 A066051 A066052
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Jan 09 2002
|
|
EXTENSIONS
|
Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 15 2005
|
|
|
Search completed in 0.002 seconds
|
