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A154811
a(n) = Fibonacci(2*n+1) mod 9.
9
1, 2, 5, 4, 7, 8, 8, 7, 4, 5, 2, 1, 1, 2, 5, 4, 7, 8, 8, 7, 4, 5, 2, 1, 1, 2, 5, 4, 7, 8, 8, 7, 4, 5, 2, 1, 1, 2, 5, 4, 7, 8, 8, 7, 4, 5, 2, 1, 1, 2, 5, 4, 7, 8, 8, 7, 4, 5, 2, 1, 1, 2, 5, 4, 7, 8, 8, 7, 4, 5, 2, 1
OFFSET
0,2
COMMENTS
Periodic with period length 12.
FORMULA
a(n) = A001519(n+1) mod 9 = A122367(n) mod 9 = |A099496(n)| mod 9.
From R. J. Mathar, Apr 10 2009: (Start)
a(n) = a(n-1) - a(n-6) + a(n-7).
G.f.: -(1 + x + 3*x^2 - x^3 + 3*x^4 + x^5 + x^6)/((x - 1)*(x^2 + 1)*(x^4 - x^2 + 1)). (End)
MATHEMATICA
Mod[Fibonacci[Range[1, 151, 2]], 9] (* Harvey P. Dale, Jul 10 2018 *)
PROG
(PARI) a(n)=fibonacci(n%12*2+1)%9 \\ Charles R Greathouse IV, Dec 21 2011
CROSSREFS
Sequence in context: A085801 A023843 A153990 * A309513 A347068 A296203
KEYWORD
nonn,easy
AUTHOR
Paul Curtz, Jan 15 2009
EXTENSIONS
Edited by R. J. Mathar, Jan 23 2009
Typo in A-number in first formula corrected by R. J. Mathar, Feb 23 2009
STATUS
approved