id:A153091 - OEIS Search Results

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Least k(n) such that k(n)*5^n*(5^n-1)+j is prime with j= -1 or 1 or both

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1, 1, 3, 1, 6, 5, 5, 1, 2, 2, 18, 12, 12, 7, 1, 1, 4, 1, 9, 2, 36, 10, 70, 1, 3, 16, 6, 3, 2, 9, 74, 4, 6, 19, 20, 8, 14, 2, 2, 62, 3, 29, 47, 11, 47, 16, 58, 1, 49, 18, 51, 3, 12, 5, 18, 23, 1, 19, 54, 7, 35, 12, 7, 1, 12, 3, 5, 121, 70, 89, 12, 61, 33, 36, 9, 17, 135, 35, 21, 23, 20, 86, 18 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`when n increases sum k(n) for i=1 to n / sum n for i=1 to n tends to 13log(5)/40 when n increases sum k(2n+1) for i=1 to n / sum (2n+1) for i=1 to n tends to log(5)/2.5 when n increases sum k(2n) for i=1 to n / sum (2*n) for i=1 to n tends to log(5)/4`
	LINKS	`Pierre CAMI, Table of n, a(n) for n = 1..1000`
	EXAMPLE	`15^1(5^1-1)-1=19 prime so k(1)=1 15^2(5^2-1)-1=599 prime as 601 so k(2)=1`
	CROSSREFS	`A152414, A152090, A152092, A152093, A152094, A152095` `Sequence in context: A109954 A153641 A133545 this_sequence A124847 A127893 A127895` `Adjacent sequences: A153088 A153089 A153090 this_sequence A153092 A153093 A153094`
	KEYWORD	`nonn`
	AUTHOR	`Pierre CAMI (pierre-cami(AT)orange.fr), Dec 18 2008`

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Last modified November 24 19:42 EST 2009. Contains 167435 sequences.

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