|
| |
|
|
A163078
|
|
Numbers n such that n$ - 1 is prime. Here '$' denotes the swinging factorial function (A056040).
|
|
3
| |
|
|
3, 4, 5, 6, 7, 10, 13, 15, 18, 30, 35, 39, 41, 47, 49, 58, 83, 86, 102, 111, 137, 151, 195, 205, 226, 229, 317, 319, 321, 368, 389, 426, 444, 477, 534, 558, 567, 738, 804, 882, 1063, 1173, 1199, 1206, 1315, 1624, 1678, 1804, 2371, 2507, 2541, 2844, 3084, 3291
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
REFERENCES
| Peter Luschny, "Divide, swing and conquer the factorial and the lcm{1,2,...,n}", preprint, April 2008.
|
|
|
LINKS
| Peter Luschny, Swinging Primes.
|
|
|
EXAMPLE
| 4$-1=6-1=5 is prime, so 4 is in the sequence.
|
|
|
MAPLE
| a := proc(n) select(x -> isprime(A056040(x)-1), [$0..n]) end:
|
|
|
MATHEMATICA
| fQ[n_] := PrimeQ[ -1 + 2^(n - Mod[n, 2])*Product[k^((-1)^(k + 1)), {k, n}]]; Select[ Range@ 3647, fQ] [From Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 09 2010]
|
|
|
CROSSREFS
| Cf. A163077, A163079, A163080, A002982.
Sequence in context: A106155 A087190 A085038 * A050034 A039056 A047562
Adjacent sequences: A163075 A163076 A163077 * A163079 A163080 A163081
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Peter Luschny (peter(AT)luschny.de), Jul 21 2009
|
|
|
EXTENSIONS
| a(42) - a(54) from Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 09 2010
|
| |
|
|
