id:A162673 - OEIS Search Results

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Number of different fixed (possibly) disconnected trominoes bounded (not necessarily tightly) by an n*n square

+0
5

0, 4, 48, 204, 580, 1320, 2604, 4648, 7704, 12060, 18040, 26004, 36348, 49504, 65940, 86160, 110704, 140148, 175104, 216220, 264180, 319704, 383548, 456504, 539400, 633100, 738504, 856548, 988204, 1134480, 1296420, 1475104, 1671648, 1887204 (list; graph; listen)

	OFFSET	`1,2`
	FORMULA	`a(n)=n(n-1)(3n^2-3n-2)/2`
	EXAMPLE	`a(2)=4: the four rotations of the (connected) L tromino`
	CROSSREFS	`Cf. A162674, A162676, A162677` `Sequence in context: A010293 A157818 A048608 this_sequence A002287 A127211 A129002` `Adjacent sequences: A162670 A162671 A162672 this_sequence A162674 A162675 A162676`
	KEYWORD	`nonn`
	AUTHOR	`David Bevan (dbevan(AT)emtex.com), Jul 27 2009`

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Last modified December 16 17:18 EST 2009. Contains 170825 sequences.

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