login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons 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 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A045695 Number of ternary words of length n (beginning 0) with autocorrelation function 2^(n-1)+1. 1
0, 1, 2, 8, 22, 70, 202, 622, 1844, 5576, 16658, 50114, 150140, 450824, 1351850, 4056794, 12168538, 36509302, 109522330, 328578142, 985717768, 2957186620, 8871509746, 26614629466, 79843738258, 239531515054, 718594094338 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..27.

FORMULA

a(2n) = 3*a(2n-1) + 2*a(n) for n >= 2; a(2n-1) = 3*a(2n-2) - a(n) for n >= 2

MAPLE

A045695 := proc(n)

    if n <=2 then

        n-1 ;

    elif type(n, 'even') then

        3*procname(n-1)+2*procname(n/2) ;

    else

        3*procname(n-1)-procname((n+1)/2) ;

    end if;

end proc: # R. J. Mathar, Oct 04 2014

CROSSREFS

Sequence in context: A137103 A089586 A339302 * A106053 A121135 A183410

Adjacent sequences:  A045692 A045693 A045694 * A045696 A045697 A045698

KEYWORD

nonn

AUTHOR

TORSTEN.SILLKE(AT)LHSYSTEMS.COM

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 December 1 22:12 EST 2021. Contains 349435 sequences. (Running on oeis4.)