A135520 - OEIS

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A135520

a(n) = 4*a(n-2).

2, 1, 8, 4, 32, 16, 128, 64, 512, 256, 2048, 1024, 8192, 4096, 32768, 16384, 131072, 65536, 524288, 262144, 2097152, 1048576, 8388608, 4194304, 33554432, 16777216, 134217728, 67108864, 536870912, 268435456, 2147483648, 1073741824 (list; graph; refs; listen; history; text; internal format)

	OFFSET	`0,1`
	LINKS	`Vincenzo Librandi,Table of n, a(n) for n = 0..1000` `Index entries for linear recurrences with constant coefficients,signature (0, 4).`
	FORMULA	`FromR. J. Mathar,corrected Apr 14 2008: (Start)` `O.g.f.: (5/(1-2x) + 3/(1+2x))/4.` `a(n) = (52^n + 3(-2)^n)/4.` `a(2n)=2A000302(n). a(2n+1)=A000302(n). (End)` `a(n) =A000079(n) terms swapped by pairs. -Paul Curtz,Apr 26 2011` `a(n) = 2^(n+(-1)^n). -Wesley Ivan Hurt,Dec 13 2013` `E.g.f.: (1/4)(5exp(2x) + 3exp(-2x)). -G. C. Greubel,Oct 17 2016`
	MAPLE	`A135520:=n->2^(n+(-1)^n); seq(A135520(n), n=0..50); #Wesley Ivan Hurt,Dec 13 2013`
	MATHEMATICA	`LinearRecurrence[{1, 4, -4}, {2, 1, 8}, 40] (Harvey P. Dale,May 25 2012 )` `LinearRecurrence[{0, 4}, {2, 1}, 32] (Ray Chandler,Aug 03 2015 )`
	PROG	`(PARI) a(n)=1<<(n+(-1)^n) \\Charles R Greathouse IV,Jun 01 2011` `(Magma) [(5/4)2^n+(3/4)(-2)^n: n in [0..40]]; //Vincenzo Librandi,Jun 02 2011`
	CROSSREFS	`Cf.A097163,A097164.` `Sequence in context:A178102A245836A368386A136230A193892A193907` `Adjacent sequences:A135517A135518A135519A135521A135522A135523`
	KEYWORD	`nonn,easy,less`
	AUTHOR	`Paul Curtz,Feb 19 2008`
	EXTENSIONS	`More terms fromR. J. Mathar,Feb 23 2008`
	STATUS	`approved`

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Last modified September 4 18:58 EDT 2024. Contains 375685 sequences. (Running on oeis4.)