A200675 Powers of 2 repeated 4 times.

1, 1, 1, 1, 2, 2, 2, 2, 4, 4, 4, 4, 8, 8, 8, 8, 16, 16, 16, 16, 32, 32, 32, 32, 64, 64, 64, 64, 128, 128, 128, 128, 256, 256, 256, 256, 512, 512, 512, 512, 1024, 1024, 1024, 1024, 2048, 2048, 2048, 2048, 4096, 4096, 4096, 4096

Offset: 0

Author

Jeremy Gardiner, Nov 20 2011

Keywords

• nonn
• easy

Comments

Run lengths in A173922.

Examples

			a(4) = 2^1 = 2.
		

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000
• Index entries for linear recurrences with constant coefficients, signature (0,0,0,2)

Crossrefs

Cf. A000079, A016116, A173862, A108105, A173922, A200678.

Programs

Mathematica

CoefficientList[Series[x*(1 + x)*(1 + x^2)/(1 - 2*x^4), {x,0,50}],x] (* or *) Table[2^(Floor[n/4]), {n,0,50}] (* G. C. Greubel, Apr 30 2017 *)

PARI

a(n)=2^(n\4) \\ Charles R Greathouse IV, Oct 03 2016

Python

def A200675(n): return 1<<(n>>2) # Chai Wah Wu, Jan 30 2023

Formula

a(n) = 2^floor(n/4).

G.f.: x*(1+x)*(1+x^2)/(1-2*x^4 ). - R. J. Mathar, Nov 21 2011

Extensions

Offset corrected by Charles R Greathouse IV, Oct 03 2016