id:A115015 - OEIS Search Results

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Sum_{i=1..n} (gcd(7,i)=1) i.

+0
2

1, 3, 6, 10, 15, 21, 21, 29, 38, 48, 59, 71, 84, 84, 99, 115, 132, 150, 169, 189, 189, 211, 234, 258, 283, 309, 336, 336, 365, 395, 426, 458, 491, 525, 525, 561, 598, 636, 675, 715, 756, 756, 799, 843, 888, 934, 981, 1029, 1029, 1079, 1130, 1182, 1235, 1289, 1344, 1344 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`a(-1-n)=a(n). - Michael Somos Jul 12 2006`
	PROGRAM	`(PARI) a(n)=binomial(n+1, 2)-7binomial(n\7+1, 2) / Michael Somos Jul 12 2006 /` `(PARI) a(n)=sum(i=1, n, i(1==gcd(7, i))) /* Michael Somos Jul 12 2006 */`
	CROSSREFS	`Cf. A115012.` `Sequence in context: A034175 A139131 A130485 this_sequence A056150 A033439 A061786` `Adjacent sequences: A115012 A115013 A115014 this_sequence A115016 A115017 A115018`
	KEYWORD	`nonn`
	AUTHOR	`njas, Feb 24 2006`

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Last modified July 23 17:35 EDT 2008. Contains 142285 sequences.

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