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A197916 Related to the periodic sequence A171654. 0
0, 1, 6, 7, 2, 3, 8, 9, 4, 5, 10, 11, 6, 7, 12, 13, 8, 9, 14, 15, 10, 11, 16, 17, 12, 13, 18, 19, 14, 15, 20, 21, 16, 17, 22, 23, 18, 19, 24, 25, 20, 21, 26, 27, 22, 23, 28, 29, 24, 25, 30, 31, 26, 27, 32, 33, 28, 29, 34, 35, 30, 31, 36, 37, 32, 33, 38, 39 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

All numbers appear twice except numbers 0,1,2,3,4,5 which appear once. - From A. Salagnad, Oct 19 2011.

LINKS

Table of n, a(n) for n=0..67.

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

FORMULA

a(n)=A171654(n) mod 10.

a(n)=Sum_k>=0 {A030308(n,k)*b(k)} with b(0)=1, b(1)=6 and b(k)=2^(k-1) for k>1.

G.f. ( -x*(-1-5*x-x^2+5*x^3) ) / ( (1+x)*(1+x^2)*(x-1)^2 ). - R. J. Mathar, Oct 20 2011

a(n) = n/2+(11-(-1)^n)/4 -5*A057077(n)/2. - R. J. Mathar, Oct 20 2011

MATHEMATICA

LinearRecurrence[{1, 0, 0, 1, -1}, {0, 1, 6, 7, 2}, 80] (* Harvey P. Dale, Jul 30 2019 *)

PROG

(PARI) a(n)=([0, 1, 0, 0, 0; 0, 0, 1, 0, 0; 0, 0, 0, 1, 0; 0, 0, 0, 0, 1; -1, 1, 0, 0, 1]^n*[0; 1; 6; 7; 2])[1, 1] \\ Charles R Greathouse IV, Jul 06 2017

CROSSREFS

Cf. A171654.

Sequence in context: A198098 A021941 A171654 * A216103 A198823 A219733

Adjacent sequences:  A197913 A197914 A197915 * A197917 A197918 A197919

KEYWORD

easy,nonn

AUTHOR

Philippe Deléham, Oct 19 2011

STATUS

approved

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Last modified August 7 15:30 EDT 2020. Contains 336276 sequences. (Running on oeis4.)