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A221849
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Number of primes of the form (x+1)^5 - x^5 with x <= 10^n.
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2
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OFFSET
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0,2
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COMMENTS
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Number of primes equal to the difference of two consecutive fifth powers (x+1)^5 - x^5 = 5x(x+1)(x^2+x+1)+1 (A121616) with x <= 10^n. Values of x = A121617. Sequence of number of primes of the form (x+1)^5 - x^5 with x <= 10^n have similar characteristics to similar sequences for natural primes and cuban primes (A221794).
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LINKS
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MATHEMATICA
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fQ[n_] := PrimeQ[(n + 1)^5 - n^5]; c = k = 0; Do[ While[k < 10^n + 1, If[ fQ@ k, c++]; k++]; Print[{n, c}], {n, 9}] (* Robert G. Wilson v, Jan 31 2013 *)
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CROSSREFS
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KEYWORD
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nonn,base
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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