A124370 - OEIS

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A124370

Expansion of 1/(1-2x^2-3x^3-x^4).

1, 0, 2, 3, 5, 12, 21, 42, 83, 159, 313, 609, 1186, 2316, 4512, 8799, 17158, 33450, 65225, 127173, 247958, 483471, 942660, 1837989, 3583691, 6987429, 13624009, 26563920, 51793996, 100987296, 196903761, 383920500 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,3`
	COMMENTS	`Diagonal sums of number triangle A124369.`
	FORMULA	`a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, C(j,n-k-j)C((j+k)/2,(j-k)/2)(1+(-1)^(j-k))/2}}`
	CROSSREFS	`Sequence in context: A089891 A004689 A183364 * A003428 A191626 A030041` `Adjacent sequences: A124367 A124368 A124369 * A124371 A124372 A124373`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), Oct 27 2006`

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Last modified February 16 23:45 EST 2012. Contains 205978 sequences.