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A156536
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Period length 12: repeat 7,5,-1,1,-5,-7,-7,-5,1,-1,5,7.
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0
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7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5, -1, 1, -5, -7, -7, -5, 1, -1, 5, 7, 7, 5
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,1
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FORMULA
| a(n) = A154811(n+6)-A154811(n).
a(n)=(1/6)*{-[(n+1) mod 12]-3*[(n+2) mod 12]+[(n+3) mod 12]-3*[(n+4) mod 12]-[(n+5) mod 12]+[(n+7) mod 12]+3*[(n+8) mod 12]-[(n+9) mod 12]+3*[(n+10) mod 12]+[(n+11) mod 12]}, with n>=0 [From Paolo P. Lava (paoloplava(AT)gmail.com), Feb 13 2009]
a(n)= -a(n-6). G.f.: -(x-1)*(7*x^4+12*x^3+11*x^2+12*x+7)/((1+x^2)*(x^4-x^2+1)). - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 10 2009
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CROSSREFS
| Cf. A154870.
Sequence in context: A021855 A145176 A093205 * A110191 A021575 A154870
Adjacent sequences: A156533 A156534 A156535 * A156537 A156538 A156539
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KEYWORD
| sign,easy
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AUTHOR
| Paul Curtz (bpcrtz(AT)free.fr), Feb 09 2009
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EXTENSIONS
| Edited by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Apr 10 2009
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