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A010697 Period 2: repeat (2,7). 6
2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2, 7, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Continued fraction expansion of A176054. - R. J. Mathar, Mar 08 2012

Decimal expansion of 3/11. - Franklin T. Adams-Watters, Nov 21 2018

LINKS

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

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

FORMULA

a(n) = -(5/2)*(-1)^n+9/2 = 7*(n mod 2)+2*[(n+1) mod 2]. - Paolo P. Lava, Oct 20 2006

G.f.: (2+7x)/((1-x)(1+x)). - R. J. Mathar, Nov 21 2011

a(n) = A010888(2^n+5^n) = A010888(A074600(n)). - Peter M. Chema, Jul 13 2016

E.g.f.: 7*sinh(x) + 2*cosh(x). - Ilya Gutkovskiy, Jul 14 2016

MATHEMATICA

Table[-5/2*(-1)^n + 9/2, {n, 0, 120}] (* or *)

Table[7 Mod[n, 2] + 2 Mod[(n + 1), 2], {n, 0, 120}] (* or *)

CoefficientList[Series[(2 + 7 x)/((1 - x) (1 + x)), {x, 0, 120}], x] (* or *)

Table[NestWhile[Total@ IntegerDigits@ # &, 2^n + 5^n, IntegerLength@ # > 1 &], {n, 0, 120}] (* Michael De Vlieger, Jul 13 2016 *)

PROG

(PARI) a(n)=if(n%2, 7, 2) \\ Charles R Greathouse IV, Oct 07 2015

CROSSREFS

Cf. A010888, A074600.

Sequence in context: A151869 A262083 A181284 * A088666 A170854 A215140

Adjacent sequences:  A010694 A010695 A010696 * A010698 A010699 A010700

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified July 17 14:44 EDT 2019. Contains 325106 sequences. (Running on oeis4.)