|
Search: id:A144717
|
|
|
| A144717 |
|
a(n)= smallest positive integer k such that a(0)*a(1)*a(2)*...*a(n) + 1 is prime. a(0)=2 |
|
+0
13
|
|
| 1, 2, 3, 5, 7, 8, 9, 11, 12, 14, 17, 20, 24, 30, 34, 44, 72, 85, 86, 92, 115, 122, 125, 132, 142, 150, 161, 162, 181, 186, 198, 224, 248, 252, 282, 283, 290, 307, 319, 321, 344, 350, 376, 445, 476, 567, 623, 676, 682, 704, 741, 749, 786, 803, 806, 893, 1014, 1046
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
EXAMPLE
|
a(1)=1 because 2*1+1=3 is prime a(2)=2 because 2*1*2+1=5 is prime a(3)=3 because 2*1*2*3+1=13 is prime 2*1*2*3*4+1=49 is not prime (omitted) a(4)=5 becuase 2*1*2*3*5+1=61 is prime
|
|
MATHEMATICA
|
k = 2; a = {}; Do[If[PrimeQ[k n + 1], k = k n; AppendTo[a, n]], {n, 1, 3000}]; a (*Artur Jasinski*)
|
|
CROSSREFS
|
A046966, A046972, 144718, A144722, A144723, A144724, A144725, A144726, A144727, A144728, A144729, A144730, A144731
Sequence in context: A134623 A156271 A158791 this_sequence A039019 A047255 A062062
Adjacent sequences: A144714 A144715 A144716 this_sequence A144718 A144719 A144720
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Artur Jasinski (grafix(AT)csl.pl), Sep 19 2008
|
|
|
Search completed in 0.002 seconds
|
