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A131081
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Periodic sequence (8, 7, 4, 1, 0, 1, 4, 7).
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5
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8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8, 7, 4, 1, 0, 1, 4, 7, 8
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Fourth column of triangular array T defined in A131074.
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LINKS
| Index entries for sequences related to linear recurrences with constant coefficients, signature (1,0,0,-1,1).
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FORMULA
| a(1) = 8, a(2) = a(8) = 7, a(3) = a(7) = 4, a(4) = a(6) = 1, a(5) = 0; for n > 8, a(n) = a(n-8).
G.f.: (8-x-3*x^2-3*x^3+7*x^4)/((1-x)*(1+x^4)).
a(n)=1/56*{(n mod 8)-13*[(n+1) mod 8]-13*[(n+2) mod 8]+[(n+3) mod 8]+15*[(n+4) mod 8]+29*[(n+5) mod 8]+29*[(n+6) mod 8]+15*[(n+7) mod 8]}, 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)%8; print1(if(r==0, 8, if(r==1||r==7, 7, if(r==2||r==6, 4, if(r==4, 0, 1)))), ", "))}
(MAGMA) m:=105; [ [8, 7, 4, 1, 0, 1, 4, 7][(n-1) mod 8 + 1]: n in [1..m] ];
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CROSSREFS
| Cf. A131074, A131028.
Sequence in context: A198561 A086253 A094883 * A158288 A193716 A196914
Adjacent sequences: A131078 A131079 A131080 * A131082 A131083 A131084
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KEYWORD
| nonn,easy,less
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AUTHOR
| Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), following a suggestion of Paul Curtz (bpcrtz(AT)free.fr), Jun 14 2007
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