login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A221049 Expansion of (1+2*x+3*x^2-x^3)/((1-x)*(1+x)*(1-2*x)*(1+2*x)). 0
1, 2, 8, 9, 36, 37, 148, 149, 596, 597, 2388, 2389, 9556, 9557, 38228, 38229, 152916, 152917, 611668, 611669, 2446676, 2446677, 9786708, 9786709, 39146836, 39146837, 156587348, 156587349, 626349396, 626349397, 2505397588, 2505397589, 10021590356, 10021590357 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..33.

Index entries for linear recurrences with constant coefficients, signature (0, 5, 0, -4).

FORMULA

a(n) = a(n-1)*4 if n even, a(n) = a(n-1)+1 if n odd.

a(2n) = (7*4^n-4)/3 = A083597(n).

a(2n+1) = (7*4^n-1)/3 = A206374(n).

a(n) = 5*a(n-2) - 4*a(n-4) with a(0)=1, a(1)=2, a(2)=8, a(3)=9.

MATHEMATICA

LinearRecurrence[{0, 5, 0, -4}, {1, 2, 8, 9}, 40] (* T. D. Noe, Apr 17 2013 *)

CROSSREFS

Cf. A083597, A206374.

Sequence in context: A075644 A088825 A181887 * A181476 A055678 A301281

Adjacent sequences:  A221046 A221047 A221048 * A221050 A221051 A221052

KEYWORD

nonn,easy

AUTHOR

Philippe Deléham, Apr 14 2013

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 27 03:21 EDT 2020. Contains 337380 sequences. (Running on oeis4.)