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A131026
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Periodic sequence (2, 2, 1, 0, 0, 1).
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11
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2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1, 0, 0, 1, 2, 2, 1
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Second column of triangular array T defined in A131022.
a(n) = A021823(n+2).
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (2,-2,1).
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FORMULA
| a(1) = a(2) = 2, a(3) = 1, a(4) = a(5) = 0, a(6) = 1; for n > 6, a(n) = a(n-6).
G.f.: (2-2*x+x^2)/((1-x)*(1-x+x^2)).
a(n)=1/30*{-3*(n mod 6)-3*[(n+1) mod 6]+2*[(n+2) mod 6]+7*[(n+3) mod 6]+7*[(n+4) mod 6]+2*[(n+5) mod 6]}, with n>=0. - Paolo P. Lava (paoloplava(AT)gmail.com), Jun 19 2007
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PROG
| (PARI) {m=105; for(n=1, m, r=(n-1)%6; print1(if(r<2, 2, if(r==2||r==5, 1, 0)), ", "))}
(MAGMA) m:=105; [ [2, 2, 1, 0, 0, 1][(n-1) mod 6 + 1]: n in [1..m] ];
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CROSSREFS
| Cf. A131022, A021823. Other columns of T are in A088911, A131027, A131028, A131029, A131030.
Sequence in context: A024712 A164965 A021823 * A014604 A015199 A051168
Adjacent sequences: A131023 A131024 A131025 * A131027 A131028 A131029
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KEYWORD
| nonn,easy
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AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), following a suggestion of Paul Curtz (bpcrtz(AT)free.fr), Jun 10 2007
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