

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
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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^(k1) for k>1.
G.f. ( x*(15*xx^2+5*x^3) ) / ( (1+x)*(1+x^2)*(x1)^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



