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A080133
Conjectured number of generalized Fermat primes of the form (n+1)^2^k + n^2^k, with k>0.
2
4, 2, 2, 2, 3, 2, 2, 2, 2, 1, 0, 3, 1, 3, 0, 1
OFFSET
1,1
COMMENTS
Primes that are the sum of consecutive integers (k=0) are excluded. Values of k <= 16 were tested. The sequence A078902 lists some of the generalized Fermat primes. Bjorn and Riesel examined generalized Fermat numbers for n <= 11 and k <= 999.
LINKS
Anders Björn and Hans Riesel, Factors of Generalized Fermat Numbers, Mathematics of Computation, Vol. 67, No. 221, Jan., 1998, pp. 441-446.
Eric Weisstein's World of Mathematics, Generalized Fermat Number
EXAMPLE
a(1) = 4 because there are four known Fermat primes (with k>0): 5, 17, 257, 65537.
MATHEMATICA
lst={}; Do[prms=0; Do[If[PrimeQ[(n+1)^2^k+n^2^k], prms++ ], {k, 1, 16}]; AppendTo[lst, prms], {n, 16}]; lst
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
T. D. Noe, Jan 30 2003
STATUS
approved