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A140724
Period 10: 1, 5, 9, 7, 7, 9, 5, 1, 3, 3 repeated.
1
1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7, 9, 5, 1, 3, 3, 1, 5, 9, 7, 7
OFFSET
0,2
COMMENTS
The last digit of A108981(n).
Also the continued fraction of (290003+sqrt(240183699293))/652402.
Also the decimal expansion of 13073/81819.
The period contains each of the 5 odd digits twice.
FORMULA
a(n)+a(n+5) = 10 = A010692(n).
a(n) = a(n+10) .
a(10*k+9+i) = a(10*k+18-i) (palindromic).
a(n) = 2*a(n-1)-2*a(n-2)+2*a(n-3)-2*a(n-4)+a(n-5). G.f.: -(1+3*x+x^2-3*x^3+3*x^4)/ ((x-1) * (x^4-x^3+x^2-x+1)).
MATHEMATICA
PadRight[{}, 120, {1, 5, 9, 7, 7, 9, 5, 1, 3, 3}] (* Harvey P. Dale, Apr 23 2020 *)
PROG
(PARI) 13073/81819. \\ Charles R Greathouse IV, Jul 21 2015
CROSSREFS
Sequence in context: A195285 A348682 A200597 * A086055 A219734 A077125
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Jul 12 2008
EXTENSIONS
Edited by R. J. Mathar, Sep 07 2009
STATUS
approved