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 A080131 Conjectured number of generalized Fermat primes of the form (n+1)^2^k + n^2^k, with k>1. 4
 3, 1, 2, 1, 2, 2, 1, 2, 1, 1, 0, 2, 1, 2, 0, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes that are the sum of consecutive integers (k=0) and consecutive squares (k=1) 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) = 3 because there are three Fermat primes (with k>1): 17, 257, 65537. MATHEMATICA lst={}; Do[prms=0; Do[If[PrimeQ[(n+1)^2^k+n^2^k], prms++ ], {k, 2, 16}]; AppendTo[lst, prms], {n, 16}]; lst CROSSREFS Cf. A019434, A078902, A080133, A080134. Sequence in context: A230500 A010281 A298421 * A319956 A082882 A188902 Adjacent sequences:  A080128 A080129 A080130 * A080132 A080133 A080134 KEYWORD nonn,hard,more AUTHOR T. D. Noe, Jan 30 2003 STATUS approved

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Last modified June 5 01:27 EDT 2020. Contains 334828 sequences. (Running on oeis4.)