|
| |
|
|
A059802
|
|
Numbers n such that 5^n - 4^n is prime.
|
|
107
| |
|
|
3, 43, 59, 191, 223, 349, 563, 709, 743, 1663, 5471, 17707, 19609, 35449, 36697, 45259, 91493, 246497
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Some of the larger entries may only correspond to probable primes.
5^1663 - 4^1663, a 1163-digit number, has been certified prime with Primo. - Rick L. Shepherd (rshepherd2(AT)hotmail.com), Nov 13 2002
4 more terms found by Predrag Minovic in 2004: 35449, 36697, 45259, 91493. Corresponding numbers of decimal digits are 24778, 25651, 31635, 63951. - Alexander Adamchuk (alex(AT)kolmogorov.com), Dec 02 2006
|
|
|
MATHEMATICA
| lst={}; Do[If[PrimeQ[5^n-4^n], (*Print[n]; *)AppendTo[lst, n]], {n, 10^5}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 26 2008]
|
|
|
PROG
| (PARI) forprime(p=2, 1e5, if(ispseudoprime(5^p-4^p), print1(p", "))) \\ Charles R Greathouse IV, Jun 10 2011
|
|
|
CROSSREFS
| Cf. A000043, A057468, A059801, etc.
Sequence in context: A155210 A157572 A137192 * A139854 A194578 A006033
Adjacent sequences: A059799 A059800 A059801 * A059803 A059804 A059805
|
|
|
KEYWORD
| nonn,hard
|
|
|
AUTHOR
| Mike Oakes (Mikeoakes2(AT)aol.com), Feb 23 2001
|
|
|
EXTENSIONS
| New term 246497 found by Jean-Louis Charton in 2008 corresponding to a probable prime with 172295 digits. Jean-Louis Charton (chartonjl(AT)wanadoo.fr), Sep 02 2009
|
| |
|
|
