id:A081238 - OEIS Search Results

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#{(i,j): mu(i)*mu(j) = -1, 1<=i<=n, 1<=j<=n}, where mu=A008683 (Moebius function).

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0, 2, 4, 4, 6, 12, 16, 16, 16, 24, 30, 30, 36, 48, 60, 60, 70, 70, 80, 80, 96, 112, 126, 126, 126, 144, 144, 144, 160, 176, 192, 192, 216, 240, 264, 264, 286, 312, 338, 338, 364, 390, 416, 416, 416, 448, 476, 476, 476, 476, 510, 510, 540, 540, 576, 576, 612, 648 (list; graph; listen)

	OFFSET	`1,2`
	COMMENT	`a(n) + A081239(n) + A081240(n) = n^2;` `a(n) = a(n-1) iff mu(n) = 0.`
	EXAMPLE	`n mu(n) ... n: 1 2 3 4 5 6 7 8` `- ------ .... \|---------------->` `1 .. +1 ..... \| + - - 0 - + - 0` `2 .. -1 ..... \| - + + 0 + - + 0` `3 .. -1 ..... \| - + + 0 + - + 0` `4 ... 0 ..... \| 0 0 0 0 0 0 0 0` `5 .. -1 ..... \| - + + 0 + - + 0 a(8)=16, as there are` `6 .. +1 ..... \| + - - 0 - + - 0 16 '-1's in the 8x8-square` `7 .. -1 ..... \| - + + 0 + - + 0 (represented as '-')` `8 ... 0 ..... \| 0 0 0 0 0 0 0 0.`
	CROSSREFS	`Cf. A070549.` `Sequence in context: A112921 A008133 A022471 this_sequence A002086 A039830 A159788` `Adjacent sequences: A081235 A081236 A081237 this_sequence A081239 A081240 A081241`
	KEYWORD	`nonn`
	AUTHOR	`Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 11 2003`

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Last modified December 20 00:58 EST 2009. Contains 171054 sequences.

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