|
Search: id:A087146
|
|
|
| A087146 |
|
Numbers n such that n!+(n+1)!-1 is prime. |
|
+0
2
|
|
| 1, 2, 3, 5, 9, 13, 14, 17, 27, 28, 33, 39, 103, 115, 205, 291, 1431, 1532, 1710, 1937
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
COMMENT
|
291 is in the sequence and also is in the sequence A087147, 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.
|
|
REFERENCES
|
H. Dubner, Factorial and primorial primes, J. Rec. Math., 19(No. 3, 1987)
|
|
EXAMPLE
|
3 is in the sequence because 3!+4!-1=29 is prime.
|
|
MATHEMATICA
|
v={}; Do[If[PrimeQ[n!+(n+1)!-1], v=Append[v, n]; Print[v]], {n, 1800}]; v
|
|
CROSSREFS
|
Cf. A087147, A051856.
Sequence in context: A079741 A000861 A108168 this_sequence A033945 A098142 A066821
Adjacent sequences: A087143 A087144 A087145 this_sequence A087147 A087148 A087149
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Farideh Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir), Aug 19 2003
|
|
EXTENSIONS
|
One more term from Ryan Propper (rpropper(AT)stanford.edu), Aug 13 2005
|
|
|
Search completed in 0.002 seconds
|
