|
| |
|
|
A087147
|
|
Numbers n such that n!+(n+1)!+1 is prime.
|
|
2
| | |
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| 291 is in the sequence and also is in the sequence A087146, thus (291!+292!-1,291!+292!+1) is a twin pair of primes. Any additional terms are greater than 1800 with the next prime having more than 5086 digits.
Next term is greater than 4200. - Gabriel Cunningham (gcasey(AT)mit.edu), Sep 09 2003
|
|
|
REFERENCES
| H. Dubner, Factorial and primorial primes, J. Rec. Math., 19 (No.3, 1987)
|
|
|
EXAMPLE
| 3 is in the sequence because 3!+4!+1=31 is prime.
|
|
|
MATHEMATICA
| v={}; Do[If[PrimeQ[n!+(n+1)!+1], v=Append[v, n]; Print[v]], {n, 1800}]; v
|
|
|
CROSSREFS
| Cf. A087146, A051856.
Primes in A118913. [From Dmitry Kamenetsky (dkamen(AT)rsise.anu.edu.au), Oct 21 2008]
Sequence in context: A115164 A003033 A193945 * A152607 A118559 A189244
Adjacent sequences: A087144 A087145 A087146 * A087148 A087149 A087150
|
|
|
KEYWORD
| more,nonn
|
|
|
AUTHOR
| Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Aug 19 2003
|
| |
|
|
