id:A106464 - OEIS Search Results

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Diagonal sums of number triangle A029578.

+0
1

1, 1, 2, 3, 3, 4, 6, 6, 5, 11, 6, 9, 15, 12, 8, 18, 9, 21, 22, 15, 11, 32, 20, 18, 27, 31, 14, 45, 15, 32, 36, 24, 41, 57, 18, 27, 43, 60, 20, 66, 21, 51, 72, 33, 23, 84, 42, 60, 57, 61, 26, 81, 67, 88, 64, 42, 29, 135, 30, 45, 105 (list; graph; listen)

	OFFSET	`0,3`
	FORMULA	`a(n)=sum{k=0..floor(n/2), gcd(n-k+1, k+1)}.`
	CROSSREFS	`Cf. A106466.` `Sequence in context: A003971 A131187 A099072 this_sequence A093003 A118096 A100989` `Adjacent sequences: A106461 A106462 A106463 this_sequence A106465 A106466 A106467`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), May 03 2005`

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.

AT&T Labs Research