OFFSET
1,1
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.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
J. Brillhart et al., Factorizations of b^n +- 1, Contemporary Mathematics, Vol. 22, Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
Victor Meally, Letter to N. J. A. Sloane, no date.
S. S. Wagstaff, Jr., The Cunningham Project
MATHEMATICA
For[ i=1, i<=10000, i++, If[ PrimeQ[ ( 2^(2n+1) - 2^(n+1) + 1)/5 ], Print[ n ] ] ]
Select[Range[5400], PrimeQ[(2^(2#+1)-2^(#+1)+1)/5]&] (* Harvey P. Dale, Jun 28 2023 *)
PROG
(PARI) is(n)=ispseudoprime((2^(2*n+1) - 2^(n+1) + 1)/5) \\ Charles R Greathouse IV, Jun 13 2017
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
EXTENSIONS
More terms from Douglas R. Burke (dburke(AT)nevada.edu)
STATUS
approved