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A285193
Expansion of 1/(1+x+2*x^2) mod 3.
1
1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0, 1, 2, 2, 0, 2, 1, 1, 0
OFFSET
0,2
COMMENTS
Periodic with period (1, 2, 2, 0, 2, 1, 1, 0).
REFERENCES
Arthur Gill, Linear Sequential Circuits, McGraw-Hill, 1966, Eq. (12-6).
FORMULA
From Colin Barker, Apr 27 2017: (Start)
G.f.: (x^6 + x^5 + 2*x^4 + 2*x^2 + 2*x + 1)/(1 - x^8).
a(n) = a(n-8) for n>7.
(End)
MAPLE
t5:=1/(1+x+2*x^2);
t6:=series(%, x, 120):
t7:=seriestolist(%);
t8:=% mod 3;
PROG
(PARI) Vec((x^6 + x^5 + 2*x^4 + 2*x^2 + 2*x + 1)/(1 - x^8) + O(x^100)) \\ Colin Barker, Apr 27 2017
CROSSREFS
Sequence in context: A286576 A322523 A333210 * A354947 A213209 A049850
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 26 2017
STATUS
approved