A147685 - OEIS

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A147685

Squares and centered square numbers interleaved.

0, 1, 1, 5, 4, 13, 9, 25, 16, 41, 25, 61, 36, 85, 49, 113, 64, 145, 81, 181, 100, 221, 121, 265, 144, 313, 169, 365, 196, 421, 225, 481, 256, 545, 289, 613, 324, 685, 361, 761, 400, 841, 441, 925, 484, 1013, 529, 1105, 576, 1201, 625, 1301, 676, 1405, 729, 1513 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,4`
	COMMENTS	`This could be called the inverse Motzkin transform of A109188 since the substitution x -> x/(1+x+x^2) in the independent variable of the g.f. A109188(x) yields this sequence here.`
	FORMULA	`a(2n)=A000290(n). a(2n+1)=A001844(n). O.g.f.: x(1+x+x^2)(1+x^2)/((1-x)^3(1+x)^3). a(n)=3a(n-2)-3a(n-4)+a(n-6).`
	CROSSREFS	`Sequence in context: A095871 A189235 A019068 * A078930 A094414 A158867` `Adjacent sequences: A147682 A147683 A147684 * A147686 A147687 A147688`
	KEYWORD	`easy,nonn`
	AUTHOR	`R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 10 2008`

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Last modified February 15 10:28 EST 2012. Contains 205763 sequences.