|
| |
|
|
A101636
|
|
a(n)=least odd prime p such that (p^(P(n))-1)/(p-1) is prime with P(i)=i-th prime, n>1.
|
|
0
| |
|
|
3, 7, 3, 5, 3, 11, 11, 113, 151, 19, 61, 53, 89, 5, 307, 19, 19, 491, 3, 11, 271, 41, 251, 271, 359, 3, 19, 79, 233, 5, 7, 13, 11, 5, 29, 71, 139, 127, 139, 2003, 5, 743, 673, 593, 383, 653, 661, 251, 6389, 2833, 223, 163, 37, 709, 131, 41, 2203, 941, 2707, 13, 1283
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 2,1
|
|
|
COMMENTS
| All primes certified using PRIMO.
|
|
|
EXAMPLE
| (3^3-1)/2=26/2=13 prime so for P(2) a(2)=3.
|
|
|
MATHEMATICA
| a = {}; Do[ p1 = Prime[n]; k = 2; While[p2 = Prime[k]; ! PrimeQ[(p2^p1 - 1)/(p2 - 1)], k++ ]; AppendTo[a, p2]; , {n, 2, 62}]; a (Ray Chandler, Jan 27 2005)
f[n_] := Block[{P = Prime[n], k = 2}, While[p = Prime[k]; !PrimeQ[(p^P - 1)/(p - 1)], k++ ]; Prime[ k]]; Table[ f[n], {n, 2, 62}] (from Robert G. Wilson v Jan 27 2005)
|
|
|
CROSSREFS
| Sequence in context: A195769 A021968 A132821 * A193534 A096247 A122583
Adjacent sequences: A101633 A101634 A101635 * A101637 A101638 A101639
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Pierre CAMI (pierre-cami(AT)bbox.fr), Jan 26 2005
|
|
|
EXTENSIONS
| Extended by Ray Chandler (rayjchandler(AT)sbcglobal.net) and Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 27 2005
|
| |
|
|
