id:A153823 - OEIS Search Results

Search: id:A153823

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Number of proper divisors of n!.

+0
2

0, 0, 1, 3, 7, 15, 29, 59, 95, 159, 269, 539, 791, 1583, 2591, 4031, 5375, 10751, 14687, 29375, 41039, 60799, 95999, 191999, 242879, 340031, 532223, 677375, 917279, 1834559, 2332799, 4665599, 5529599, 7864319, 12165119, 16422911 (list; graph; listen)

	OFFSET	`0,4`
	COMMENT	`a(n) is the number of proper divisors of factorial number A000142(n).`
	FORMULA	`a(n) = A000005(A000142(n))-1 = A032741(A000142(n)) = A027423(n)-1.`
	CROSSREFS	`Cf. A000005, A000142, A027423, A032741.` `Cf. A153823, A153825. [From Omar E. Pol (info(AT)polprimos.com), Jan 17 2009]` `Sequence in context: A023608 A132780 A018087 this_sequence A080011 A120538 A146019` `Adjacent sequences: A153820 A153821 A153822 this_sequence A153824 A153825 A153826`
	KEYWORD	`nonn`
	AUTHOR	`Omar E. Pol (info(AT)polprimos.com), Jan 02 2009`
	EXTENSIONS	`More terms from Omar E. Pol (info(AT)polprimos.com), Jan 17 2009`

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.

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