id:A091369 - OEIS Search Results

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a(n) = sum_{i=1..n} eulerphi(i)*ceil(n/i).

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1, 3, 7, 12, 20, 27, 39, 50, 64, 77, 97, 112, 136, 155, 177, 200, 232, 255, 291, 318, 350, 381, 425, 456, 500, 537, 581, 620, 676, 713, 773, 820, 872, 921, 979, 1026, 1098, 1153, 1215, 1270, 1350, 1403, 1487, 1550, 1618, 1685, 1777, 1840, 1930, 1999, 2081, 2156 (list; graph; listen)

	OFFSET	`1,2`
	MATHEMATICA	`A091369[n_] := Sum[EulerPhi[i]*Ceiling[n/i], {i, n}] (from Robert G. Wilson v Mar 02 2004)`
	CROSSREFS	`Cf. A000217.` `Sequence in context: A039677 A011899 A002498 this_sequence A036698 A132273 A130050` `Adjacent sequences: A091366 A091367 A091368 this_sequence A091370 A091371 A091372`
	KEYWORD	`nonn`
	AUTHOR	`Jon Perry (perry(AT)globalnet.co.uk), Mar 01 2004`
	EXTENSIONS	`More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 02 2004`

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Last modified March 20 09:10 EDT 2010. Contains 173642 sequences.

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