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A117450
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Expansion of (1-x+x^2+x^5)/((1-x)^2*(1-x^5)).
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2
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1, 1, 2, 3, 4, 7, 9, 12, 15, 18, 23, 27, 32, 37, 42, 49, 55, 62, 69, 76, 85, 93, 102, 111, 120, 131, 141, 152, 163, 174, 187, 199, 212, 225, 238, 253, 267, 282, 297, 312, 329, 345, 362, 379, 396, 415, 433, 452, 471, 490, 511
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| First differences are A117451. Second differences are A117452.
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FORMULA
| a(n)=2a(n-1)-a(n-2)+a(n-5)-2a(n-6)+a(n-7); a(n)=sum{k=0..n, C(n-k,L(k/5))}, where L(j/p) is the Legendre symbol of j and p; a(n)=(1/10-sqrt(5)/50)*cos(4*pi*n/5+2*pi/5)+sqrt(1/10+sqrt(5)/50)*sin(4*pi*n/5+2*pi/5) -(1/10+sqrt(5)/50)*cos(2*pi*n/5+pi/5)+sqrt(1/10-sqrt(5)/50)*sin(2*pi*n/5+pi/5) +(n^2+n+3)/5.
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CROSSREFS
| Sequence in context: A023546 A191989 A084913 * A132381 A073152 A051061
Adjacent sequences: A117447 A117448 A117449 * A117451 A117452 A117453
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Mar 16 2006
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