|
Search: id:A004063
|
|
|
| A004063 |
|
Numbers n such that (7^n - 1)/6 is prime. (Formerly M3836)
|
|
+0 15
|
| |
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Base 7 repunit primes. - Paul Bourdelais (paul.bourdelais(AT)gd-ais.com), Aug 31 2007
a(7)=35201 is a probable prime with trial factoring to 7e12 and Fermat base 2 primality test. - Paul Bourdelais (paul.bourdelais(AT)gd-ais.com), Aug 31 2007
|
|
REFERENCES
|
J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and later supplements.
H. Dubner, Generalized repunit primes, Math. Comp., 61 (1993), 927-930.
|
|
LINKS
|
J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
S. S. Wagstaff, Jr., The Cunningham Project
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
H. Lifchitz, Mersenne and Fermat primes field
|
|
MATHEMATICA
|
For[n = 1, n <= 20000, n++, If[PrimeQ[(7^n - 1)/6 ], Print[n]]] - Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 09 2006
|
|
CROSSREFS
|
Sequence in context: A117437 A106046 A117527 this_sequence A005764 A099974 A117077
Adjacent sequences: A004060 A004061 A004062 this_sequence A004064 A004065 A004066
|
|
KEYWORD
|
nonn,hard
|
|
AUTHOR
|
njas
|
|
EXTENSIONS
|
a(6) from Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 09 2005
a(7) from Paul Bourdelais (paul.bourdelais(AT)gd-ais.com), Aug 31 2007
|
|
|
Search completed in 0.002 seconds
|