id:A110145 - OEIS Search Results

Search: id:A110145

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Sum{k=0..n, C(n,k)^2*mod(k,2)}.

+0
1

0, 1, 4, 10, 32, 126, 472, 1716, 6400, 24310, 92504, 352716, 1351616, 5200300, 20060016, 77558760, 300533760, 1166803110, 4537591960, 17672631900, 68923172032, 269128937220, 1052049834576, 4116715363800, 16123800489472 (list; graph; listen)

	OFFSET	`0,3`
	COMMENT	`Interleaves A002458 and A037964.`
	FORMULA	`a(n)=sum{k=0..n, C(n, k)^2(1-(-1)^k)/2}; a(n)=C(2n-1, n-1)(1-(-1)^n)/2+(C(2n, n)/2-(-1)^(n/2)C(n, floor(n/2))/2)(1+(-1)^n)/2.`
	CROSSREFS	`Sequence in context: A137954 A028283 A151746 this_sequence A162427 A165730 A052366` `Adjacent sequences: A110142 A110143 A110144 this_sequence A110146 A110147 A110148`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jul 13 2005`

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Last modified December 11 12:57 EST 2009. Contains 170656 sequences.

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