A106469 - OEIS

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A106469

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

1, 2, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4, 2, 4 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	COMMENTS	`Row sums of number triangle A106468.`
	FORMULA	`a(0)=1, a(n)=(2-0^((n-1)/2))(1-(-1)^n)+(2-0^(n/2))(1+(-1)^n)/2, n>1.`
	CROSSREFS	`Sequence in context: A100374 A045841 A040003 * A082508 A193562 A163824` `Adjacent sequences: A106466 A106467 A106468 * A106470 A106471 A106472`
	KEYWORD	`easy,nonn`
	AUTHOR	`Paul Barry (pbarry(AT)wit.ie), May 03 2005`

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Last modified February 17 17:35 EST 2012. Contains 206061 sequences.