id:A070236 - OEIS Search Results

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Sum(k=1,n,core(k)-phi(k)) where core(k) is the square-free part of k.

+0
1

0, 1, 2, 1, 2, 6, 7, 5, 0, 6, 7, 6, 7, 15, 22, 15, 16, 12, 13, 10, 19, 31, 32, 30, 11, 25, 10, 5, 6, 28, 29, 15, 28, 46, 57, 46, 47, 67, 82, 76, 77, 107, 108, 99, 80, 104, 105, 92, 51, 33, 52, 41, 42, 30, 45, 35, 56, 86, 87, 86, 87, 119, 90, 59, 76, 122, 123, 108, 133, 179, 180 (list; graph; listen)

	OFFSET	`1,3`
	COMMENT	`Always =>0.`
	FORMULA	`a(n) = A069891(n)- A002088(n) asymptotically : a(n)=(Pi^2/30-3/Pi^2)*n^2+0(nln(n))`
	PROGRAM	`(PARI) for(n=1, 100, print1(sum(i=1, n, core(i)-eulerphi(i)), ", "))`
	CROSSREFS	`Sequence in context: A153896 A074727 A059587 this_sequence A020825 A110422 A131804` `Adjacent sequences: A070233 A070234 A070235 this_sequence A070237 A070238 A070239`
	KEYWORD	`easy,nonn`
	AUTHOR	`Benoit Cloitre (benoit7848c(AT)orange.fr), May 08 2002`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

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