A080226 - OEIS

This site is supported by donations to The OEIS Foundation.

A080226

Number of deficient divisors of n.

1, 2, 2, 3, 2, 3, 2, 4, 3, 4, 2, 4, 2, 4, 4, 5, 2, 4, 2, 5, 4, 4, 2, 5, 3, 4, 4, 5, 2, 6, 2, 6, 4, 4, 4, 5, 2, 4, 4, 6, 2, 6, 2, 6, 6, 4, 2, 6, 3, 6, 4, 6, 2, 5, 4, 6, 4, 4, 2, 7, 2, 4, 6, 7, 4, 6, 2, 6, 4, 7, 2, 6, 2, 4, 6, 6, 4, 6, 2, 7, 5, 4, 2, 7, 4, 4, 4, 7, 2, 8, 4, 6, 4, 4, 4, 7, 2, 6, 6, 7, 2, 6, 2, 7, 8 (list; graph; refs; listen; history; internal format)

	OFFSET	`1,2`
	COMMENTS	`Number of divisors d of n with sigma(d)<2*d (sigma=A000203); A080224(n)+A080225(n)+a(n)=A000005(n).`
	LINKS	`Eric Weisstein's World of Mathematics, Deficient Number.`
	EXAMPLE	`All 4 divisors of n=21 are deficient: 1=A005100(1), 3=A005100(3), 7=A005100(6) and 21=A005100(17), therefore a(21)=4.`
	CROSSREFS	`Cf. A005100, A000203.` `Sequence in context: A135981 A135615 A166469 * A060741 A125747 A060129` `Adjacent sequences: A080223 A080224 A080225 * A080227 A080228 A080229`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Feb 07 2003`

Content is available under The OEIS End-User License Agreement .

Last modified February 14 17:34 EST 2012. Contains 205644 sequences.