A110524 - OEIS

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A110524

Expansion of (1+x)/(1+2x+2x^3).

1, -1, 2, -6, 14, -32, 76, -180, 424, -1000, 2360, -5568, 13136, -30992, 73120, -172512, 407008, -960256, 2265536, -5345088, 12610688, -29752448, 70195072, -165611520, 390727936, -921846016, 2174915072, -5131286016, 12106264064, -28562358272, 67387288576, -158987105280 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`Diagonal sums of number triangle A110522.`
	FORMULA	`a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, (-1)^(n-k-j)C(n-k, j)(-3)^(j-k)*C(k, j-k)}}`
	CROSSREFS	`Sequence in context: A131352 A051485 A077999 * A083404 A089351 A005380` `Adjacent sequences: A110521 A110522 A110523 * A110525 A110526 A110527`
	KEYWORD	`easy,sign`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Jul 24 2005`

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Last modified February 16 11:51 EST 2012. Contains 205908 sequences.