id:A078718 - OEIS Search Results

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Let f(i,j) = Sum(binomial(2*i,k)*binomial(2*j,i+j-k)*(-1)^(i+j-k),k=0..2*i) (this is essentially the same as the triangle in A068555); then a(n) = f(n,n-2)/2.

+0
2

0, 1, 3, -5, 14, -45, 154, -546, 1980, -7293, 27170, -102102, 386308, -1469650, 5616324, -21544100, 82907640, -319929885, 1237518450, -4796857230, 18627909300, -72457790790, 282257178060, -1100982015900, 4299680491080, -16809921068850, 65785111513524, -257683159276956 (list; graph; listen)

	OFFSET	`0,3`
	CROSSREFS	`Cf. A068555. Apart perhaps from signs, f(n,0) and f(n,n) give A000984, f(n,1) gives A002420, f(n,n-1) gives 2*A000984.` `Sequence in context: A007136 A052974 A006395 this_sequence A081393 A129326 A118562` `Adjacent sequences: A078715 A078716 A078717 this_sequence A078719 A078720 A078721`
	KEYWORD	`sign`
	AUTHOR	`njas, Dec 20 2002`

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Last modified September 5 23:56 EDT 2008. Contains 143485 sequences.

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