A122380 - OEIS

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A122380

Numbers n such that n^2 > P(n)!, where P(n) is the greatest prime factor of n.

2, 3, 4, 6, 8, 9, 12, 15, 16, 18, 20, 24, 25, 27, 30, 32, 36, 40, 45, 48, 50, 54, 60, 64, 72, 75, 80, 81, 84, 90, 96, 98, 100, 105, 108, 112, 120, 125, 126, 128, 135, 140, 144, 147, 150, 160, 162, 168, 175, 180, 189, 192, 196, 200, 210, 216, 224, 225, 240, 243, 245 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,1`
	COMMENTS	`It is conjectured that n^2 < P(n)! for almost all n.`
	REFERENCES	`J. Sondow, A geometric proof that e is irrational and a new measure of its irrationality, Amer. Math. Monthly 113 (2006) 637-641.`
	LINKS	`I ndex entries for sequences related to factorial numbers.` `J. Sondow, A geometric proof that e is irrational and a new measure of its irrationality` `Eric Weisstein's World of Mathematics, Smarandache Function`
	EXAMPLE	`15^2 = 225 > 120 = 5! = P(15)!, so 15 is a member.`
	CROSSREFS	`Cf. A000290, A006530, A057109, A102068, A122378, A122379.` `Sequence in context: A116621 A036407 A145807 * A033501 A097273 A006446` `Adjacent sequences: A122377 A122378 A122379 * A122381 A122382 A122383`
	KEYWORD	`nonn`
	AUTHOR	`Jonathan Sondow (jsondow(AT)alumni.princeton.edu), Sep 03 2006`

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Last modified February 17 11:46 EST 2012. Contains 206011 sequences.