id:A015631 - OEIS Search Results

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Number of ordered triples of integers from [ 1..n ] with no global factor.

+0
6

1, 3, 8, 15, 29, 42, 69, 95, 134, 172, 237, 287, 377, 452, 552, 652, 804, 915, 1104, 1252, 1450, 1635, 1910, 2106, 2416, 2674, 3007, 3301, 3735, 4027, 4522, 4914, 5404, 5844, 6432, 6870, 7572, 8121, 8805, 9389, 10249, 10831, 11776, 12506 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`Number of integer-sided triangles with at least two sides <= n and sides relatively prime. - Henry Bottomley (se16(AT)btinternet.com), Sep 29 2006`
	FORMULA	`a(n) = (A071778(n)+3A018805(n)+2)/6. - Vladeta Jovovic (vladeta(AT)eunet.rs), Dec 01 2004` `Partial sums of the Moebius transform of the triangular numbers (A007438) - Steve Butler (sbutler(AT)math.ucsd.edu), Apr 18 2006` `a(n) = 2A123324(n) - A046657(n) for n>1. - Henry Bottomley (se16(AT)btinternet.com), Sep 29 2006` `Row sums of triangle A134543 - Gary W. Adamson (qntmpkt(AT)yahoo.com), Oct 31 2007`
	CROSSREFS	`Cf. A015616.` `Cf. A134543.` `Sequence in context: A036419 A054107 A097589 this_sequence A116686 A135350 A068038` `Adjacent sequences: A015628 A015629 A015630 this_sequence A015632 A015633 A015634`
	KEYWORD	`nonn`
	AUTHOR	`Olivier Gerard (olivier.gerard(AT)gmail.com)`

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Last modified December 7 23:50 EST 2009. Contains 170430 sequences.

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