A010724 Period 2: repeat (6,8).

6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6, 8, 6

Offset

0,1

Comments

Decimal expansion of 68/99. - David A. Corneth, Oct 18 2016

Continued fraction expansion of (6 + sqrt(39))/2 = A176401. - Elmo R. Oliveira, Oct 12 2025

Links

Table of n, a(n) for n=0..80.

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

Formula

a(n) = (-1)^(n+1) + 7. - Paolo P. Lava, Oct 27 2006

G.f.: 2*(-3-4*x)/((x-1)*(1+x)). - R. J. Mathar, Nov 21 2011

a(0)=6, a(n) = 10 - eulerphi(a(n-1)) for n>0. - Alexander R. Povolotsky, Oct 16 2016

From Elmo R. Oliveira, Oct 12 2025: (Start)

E.g.f.: 6*cosh(x) + 8*sinh(x).

a(n) = 2*A010702(n). (End)

Mathematica

NestList[10 - EulerPhi@ # &, 6, 120] (* or *)
CoefficientList[Series[(-6 - 8 x)/((x - 1) (1 + x)), {x, 0, 120}], x] (* Michael De Vlieger, Oct 21 2016 *)

Prog

(PARI) a(n)=6+n%2*2 \\ Charles R Greathouse IV, Dec 08 2015

Crossrefs

Cf. A010702, A176401.

Sequence in context: A088751 A153627 A094540 * A196822 A065356 A019797

Adjacent sequences: A010721 A010722 A010723 * A010725 A010726 A010727

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved