id:A108714 - OEIS Search Results

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a(n)=minimal value of k, such that n^2+k^2 or (n^2+k^2)/2 are primes.

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1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 7, 2, 1, 1, 1, 2, 5, 1, 1, 4, 5, 3, 1, 1, 1, 2, 5, 1, 11, 4, 3, 2, 5, 1, 1, 2, 3, 1, 1, 4, 5, 3, 9, 1, 5, 2, 13, 1, 7, 1, 3, 3 (list; graph; listen)

	OFFSET	`1,7`
	COMMENT	`I am attempting to complete a proof that for every natural number n, there is at least one prime of the form n^2+k^2 or (n^2+k^2)/2 with 1<=k<=n.`
	EXAMPLE	`a(3)=1 because (3^2+1)/2=5 (prime)` `a(7)=2 ------> 7^2+2^2=53 (prime)` `a(12)=7 -----> 12^2+7^2=193 (prime)` `a(23)=3 -----> (23^2+3^2)/2=269 (prime)` `a(48)=13 ----> 48^2+13^2=2473 (prime)`
	CROSSREFS	`Sequence in context: A140737 A108756 A106178 this_sequence A135508 A030413 A139434` `Adjacent sequences: A108711 A108712 A108713 this_sequence A108715 A108716 A108717`
	KEYWORD	`nonn`
	AUTHOR	`Robin Garcia (verob99(AT)teleline.es), Jun 20 2005`

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Last modified August 29 17:54 EDT 2008. Contains 143238 sequences.

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