A014236 - OEIS

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A014236

G.f.: 2*x*(1-x)/((1-2*x)(1-2*x^2)).

0, 2, 2, 8, 12, 32, 56, 128, 240, 512, 992, 2048, 4032, 8192, 16256, 32768, 65280, 131072, 261632, 524288, 1047552, 2097152, 4192256, 8388608, 16773120, 33554432, 67100672, 134217728, 268419072 (list; graph; refs; listen; history; internal format)

	OFFSET	`0,2`
	COMMENTS	`Number of symmetric chiral (optically active) isomers possible for organic compounds with n distinct carbon atoms.`
	LINKS	`Index entries for sequences related to linear recurrences with constant coefficients, signature (2,2,-4).`
	FORMULA	`a(n) = 2*A007179(n). - R. J. Mathar, Nov 14 2011`
	MAPLE	`f := n -> if n mod 2 = 0 then 2^n-2^(n/2) else 2^n; fi;`
	CROSSREFS	`Second differences of A027556.` `Sequence in context: A008828 A053414 A189837 * A087955 A026537 A089248` `Adjacent sequences: A014233 A014234 A014235 * A014237 A014238 A014239`
	KEYWORD	`nonn,easy`
	AUTHOR	`Paul F. Hudrlik (hudrlik(AT)scs.howard.edu)`
	EXTENSIONS	`G.f. corrected by Olivier Gérard, Nov 13 2011`

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Last modified February 15 09:35 EST 2012. Contains 205753 sequences.