|
| |
|
|
A131800
|
|
Period 4: repeat 1,2,5,6.
|
|
5
| |
|
|
1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6, 1, 2, 5, 6
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
COMMENTS
| Terms of the simple continued fraction of 4/[3*sqrt(21)-11]. [From Paolo P. Lava (paoloplava(AT)gmail.com), Aug 05 2009]
Decimal expansion of 1256/9999. [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), May 20 2010]
|
|
|
LINKS
| Salvatore Gambino, Terne pitagoriche primitive
Index to sequences with linear recurrences with constant coefficients, signature (0,0,0,1).
|
|
|
FORMULA
| a(n) = (7+(-1)^n+4*(-1)^(2*n+1-(-1)^n)/4)/2
O.g.f.: -(1+2x+5x^2+6x^3)/((x-1)(x+1)(x^2+1)) . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 13 2008
a(n)=(1/6)*{11*(n mod 4)+2*[(n+1) mod 4]-[(n+2) mod 4]+2*[(n+3) mod 4]}, with n>=0 - Paolo P. Lava (paoloplava(AT)gmail.com), Jan 28 2008
a(n)=7/2-(1-I)*I^n-1/2*(-1)^n-(1+I)*(-I)^n, with n>=0 and I=sqrt(-1) - Paolo P. Lava (paoloplava(AT)gmail.com), Jul 17 2008
A000111(n+2) mod 10.
a(n) = 7/2-2*cos(Pi*n/2)-2*sin(Pi*n/2)-(-1)^n/2. - R. J. Mathar, Oct 08 2011
|
|
|
CROSSREFS
| Cf. A178131 (decimal expansion of (11+3*sqrt(21))/17).
Sequence in context: A111987 A004650 A138279 * A086038 A200136 A134387
Adjacent sequences: A131797 A131798 A131799 * A131801 A131802 A131803
|
|
|
KEYWORD
| nonn,easy
|
|
|
AUTHOR
| Salvatore Gambino (salvatore.gambino(AT)fastwebnet.it), Oct 04 2007
|
|
|
EXTENSIONS
| More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 13 2008
|
| |
|
|
