login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”).

Other ways to Give
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A239905 If n <= 5 then a(n) = 1, if 6 <= n <= 8 then 2, if n = 9 or 10 then 3, if n = 11, 12 or 13 then n-7; otherwise a(n) = 2*a(n - 4) + a(n - 12). 1
1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 5, 6, 7, 9, 11, 13, 16, 20, 24, 29, 35, 44, 53, 64, 77, 97, 117, 141, 170, 214, 258, 311, 375, 472, 569, 686, 827, 1041, 1255, 1513, 1824, 2296, 2768, 3337, 4023, 5064, 6105, 7360, 8873, 11169, 13465, 16233, 19570, 24634, 29698, 35803, 43163, 54332, 65501 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

R. S. Booth, An odd order search problem, SIAM J. Algebraic Discrete Methods 3 (1982), no. 1, 135--143. MR0644964 (83d:90106). See sequence U(n).

Index entries for linear recurrences with constant coefficients, signature (0,0,0,2,0,0,0,0,0,0,0,1).

FORMULA

G.f.: x*(x^12-x^11+x^9-x^8+x^4-x^3-x^2-x-1) / (x^12+2*x^4-1). - Colin Barker, Apr 18 2014

MAPLE

U:=proc(n) option remember; if n <= 5 then 1

elif n <= 8 then 2

elif n <= 10 then 3

elif n = 11 then 4

elif n = 12 then 5

elif n = 13 then 6

else 2*U(n-4)+U(n-12); fi; end;

[seq(U(n), n=1..60)];

MATHEMATICA

CoefficientList[Series[(x^12 - x^11 + x^9 - x^8 + x^4 - x^3 - x^2 - x - 1)/(x^12 + 2 x^4 - 1), {x, 0, 40}], x] (* Vincenzo Librandi, Apr 19 2014 *)

LinearRecurrence[{0, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 4, 5, 6}, 70] (* Harvey P. Dale, Mar 30 2019 *)

CROSSREFS

Sequence in context: A120170 A136421 A274159 * A016085 A018122 A074732

Adjacent sequences: A239902 A239903 A239904 * A239906 A239907 A239908

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Apr 07 2014

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified December 7 19:19 EST 2022. Contains 358669 sequences. (Running on oeis4.)