|
Search: id:A101446
|
|
|
| A101446 |
|
a(n)= least k such that n^k*(n^k-1)-1 is prime with n > 1. |
|
+0
2
|
|
| 2, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 10, 1, 5, 1, 1, 2, 2, 1, 1, 1, 2, 4, 1, 4, 1, 12, 1, 328, 1, 1, 6, 24, 77, 1, 8, 75, 1, 1, 2, 1, 2, 13, 1, 1, 1, 14, 1, 3, 1, 45, 3, 1, 1, 1, 1, 8, 625, 1, 1, 22, 3, 3, 1, 1, 1, 11, 1, 4, 1, 2
(list; graph; listen)
|
|
|
OFFSET
|
2,1
|
|
|
EXAMPLE
|
2^2*(2^2-1)-1=11 prime so a(2)=2.
|
|
MATHEMATICA
|
f[n_] := Block[{k = 1, c}, While[c = n^k; ! PrimeQ[c*(c - 1) - 1], k++ ]; Return[k]; ]; Table[f[n], {n, 2, 72}] (*Chandler*)
|
|
CROSSREFS
|
Cf. A101406.
Sequence in context: A115413 A069283 A033630 this_sequence A062760 A014649 A070084
Adjacent sequences: A101443 A101444 A101445 this_sequence A101447 A101448 A101449
|
|
KEYWORD
|
nonn,more
|
|
AUTHOR
|
Pierre CAMI (pierrecami(AT)tele2.fr), Jan 24 2005
|
|
EXTENSIONS
|
a(55)-a(72) from Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 27 2005
a(73)>2475. - Ray Chandler (rayjchandler(AT)sbcglobal.net), Jan 27 2005
|
|
|
Search completed in 0.002 seconds
|
