id:A128557 - OEIS Search Results

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a(n) = the largest positive integer k such that (n!/k!) has at least n positive divisors.

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1, 1, 1, 2, 3, 4, 5, 6, 7, 8, 8, 10, 10, 11, 13, 14, 14, 15, 16, 17, 19, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 34, 34, 35, 35, 37, 38, 39, 39, 41, 42, 43, 44, 45, 46, 47, 48, 49, 49, 51, 52, 53, 54, 55, 55, 57, 57, 59, 59, 61, 62, 63, 63, 64, 65, 67, 67, 69, 69 (list; graph; listen)

	OFFSET	`1,4`
	LINKS	`Leroy Quet, Home Page (listed in lieu of email address)`
	EXAMPLE	`a(11) = 8 because 11!/8! = 91011 = 990 has 24 divisors (and 24 is >= 11), but 11!/9! = 10*11 = 110 has 8 divisors (and 8 is < 11).`
	MAPLE	`with(numtheory): a:=proc(n) local A, k: A:={}: for k from 1 to n do if tau(n!/k!)>=n then A:=A union {k} else A:=A fi od: A[nops(A)]; end: seq(a(n), n=1..90); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 23 2007`
	CROSSREFS	`Cf. A128558, A128559.` `Sequence in context: A079631 A160755 A017873 this_sequence A103303 A093691 A004176` `Adjacent sequences: A128554 A128555 A128556 this_sequence A128558 A128559 A128560`
	KEYWORD	`nonn`
	AUTHOR	`Leroy Quet Mar 10 2007`
	EXTENSIONS	`More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Mar 23 2007`

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Last modified November 23 17:09 EST 2009. Contains 167438 sequences.

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