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Search: id:A068073
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| A068073 |
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A simple periodic sequence. |
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+0
2
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| 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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Expansion of (1 + 2x + 3x^2 + 2x^3)/(1 - x^4)
Conjecture: a(n)=sum{k=0..n, e^(i*pi*(A000120(A001045(n))-A0001045(A000120(n))))}, i=sqrt(-1). - Paul Barry (pbarry(AT)wit.ie), Jan 14 2005
G.f.: (1+x+2x^2)/(1-x+x^2-x^3); a(n)=2-cos(pi*n/2); - Paul Barry (pbarry(AT)wit.ie), Jan 14 2005
a(n)=(1/12)*[7*(n mod 4)+7*((n+1) mod 4)+(n+2) mod 4+(n+3) mod 4] - Paolo P. Lava (ppl(AT)spl.at), Oct 09 2006
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MATHEMATICA
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CoefficientList[ Series[(1 + 2x + 3x^2 + 2x^3)/(1 - x^4), {x, 0, 85}], x]
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CROSSREFS
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Cf. A000034, A028356.
Sequence in context: A053555 A124160 A002175 this_sequence A032452 A084199 A030314
Adjacent sequences: A068070 A068071 A068072 this_sequence A068074 A068075 A068076
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KEYWORD
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easy,nonn
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 01 2002
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