login
This site is supported by donations to The OEIS Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing.
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A066043 a(1) = 1; for m > 0, a(2m) = 2m, a(2m+1) = 4m+2. 5
1, 2, 6, 4, 10, 6, 14, 8, 18, 10, 22, 12, 26, 14, 30, 16, 34, 18, 38, 20, 42, 22, 46, 24, 50, 26, 54, 28, 58, 30, 62, 32, 66, 34, 70, 36, 74, 38, 78, 40, 82, 42, 86, 44, 90, 46, 94, 48, 98, 50, 102, 52, 106, 54, 110, 56, 114, 58, 118, 60, 122, 62, 126, 64, 130, 66, 134, 68 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Length of period of sequences r(k,n) = floor(sinh(1)*k!) - n*floor(sinh(1)*k!/n) when n is fixed. - Benoit Cloitre, Jun 22 2003

LINKS

Harry J. Smith, Table of n, a(n) for n = 1..1000

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

FORMULA

O.g.f.: (x+2x^2+4x^3-x^5)/(1-x^2)^2. - Len Smiley, Dec 05 2001

a(n)*a(n+3) = -4 + a(n+1)*a(n+2).

From Harry J. Smith, Nov 08 2009: (Start)

a(n) = A109043(n), n > 1.

a(n) = 2*A026741(n), n > 1. (End)

EXAMPLE

r(k,7) is sequence 1, 2, 0, 0, 1, 6, 1, 1, 3, 2, 2, 3, 5, 0, 1, 2, 0, 0, 1, 6, 1, 1, 3, 2, 2, 3, 5, 0.... which is periodic with period (1, 2, 0, 0, 1, 6, 1, 1, 3, 2, 2, 3, 5, 0) of length 14 = a(7).

PROG

(PARI) a(n)=if(n<2, 1, if(n%2, 2*n, n))

(PARI) { for (n=1, 1000, a=if (n>1 && n%2, 2*n, n); write("b066043.txt", n, " ", a) ) } \\ Harry J. Smith, Nov 08 2009

CROSSREFS

Sequence in context: A074208 A227389 A015906 * A238642 A145019 A066678

Adjacent sequences:  A066040 A066041 A066042 * A066044 A066045 A066046

KEYWORD

easy,nonn

AUTHOR

George E. Antoniou (george.antoniou(AT)montclair.edu), Nov 30 2001

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 8 12:07 EST 2019. Contains 329862 sequences. (Running on oeis4.)