id:A143943 - OEIS Search Results

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The Wiener index of a chain of n squares joined at vertices (i.e. joined like <><><>...<>; here <> is a square!). The Wiener index of a connected graph is the sum of distances between all unordered pairs of vertices in the graph.

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8, 40, 114, 248, 460, 768, 1190, 1744, 2448, 3320, 4378, 5640, 7124, 8848, 10830, 13088, 15640, 18504, 21698, 25240, 29148, 33440, 38134, 43248, 48800, 54808, 61290, 68264, 75748, 83760, 92318, 101440, 111144, 121448, 132370, 143928 (list; graph; listen)

	OFFSET	`1,1`
	FORMULA	`a(n)=n(2+3n+3n^2).` `G.f. = 2z(2 + z)^2/(1-z)^4.` `a(n)=Sum(k*A143942(n,k), k=1..2n).`
	EXAMPLE	`a(1)=8 because in the graph <> we have 8 edges.`
	MAPLE	`seq(n(2+3n+3*n^2), n=1..40);`
	CROSSREFS	`A143942` `Sequence in context: A120931 A069083 A014642 this_sequence A135796 A105374 A162668` `Adjacent sequences: A143940 A143941 A143942 this_sequence A143944 A143945 A143946`
	KEYWORD	`nonn`
	AUTHOR	`Emeric Deutsch (deutsch(AT)duke.poly.edu), Sep 06 2008`

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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.

AT&T Labs Research