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A010680
Decimal expansion of 1/11.
4
0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9, 0, 9
OFFSET
0,2
COMMENTS
Period 2: repeat [0,9].
FORMULA
a(n) = (9/2)*(1 - (-1)^n) = 9*(n mod 2). - Paolo P. Lava, Oct 31 2006
From Elmo R. Oliveira, Jan 15 2024: (Start)
a(n) = a(n-2) for n >= 2.
a(n) = 3 * A010674(n).
G.f.: 9*x/(1-x^2).
E.g.f.: 9*sinh(x). (End)
a(n) = 9 * A000035(n). - Alois P. Heinz, Jan 16 2024
EXAMPLE
1/11 = 0.0909090909090909090909090909090909090909090909090909090909...
MATHEMATICA
RealDigits[1/11, 10, 100][[1]] (* Alonso del Arte, Mar 11 2018 *)
PROG
(PARI) a(n) = 9*(n%2); \\ Altug Alkan, Mar 25 2018
CROSSREFS
Bisections give: A000004, A010734.
Sequence in context: A343587 A021015 A372947 * A248724 A371649 A278144
KEYWORD
nonn,easy,cons
STATUS
approved