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Search: id:A045873
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| 0, 1, 2, -1, -12, -19, 22, 139, 168, -359, -1558, -1321, 5148, 16901, 8062, -68381, -177072, -12239, 860882, 1782959, -738492, -10391779, -17091098, 17776699, 121008888, 153134281, -298775878, -1363223161, -1232566932
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Partial sums of A006495. - Paul Barry (pbarry(AT)wit.ie), Mar 16 2006
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FORMULA
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G.f.: x/(1-2x+5x^2); E.g.f. : exp(x)sin(2x)/2; a(n)=2a(n-1)-5a(n-2), a(0)=0, a(1)=1; a(n)=((1+i2)^n-(1-i2)^n)/(4i); a(n)=Im{(1+i2)^n/2}; a(n)=sum{k=0..floor(n/2), C(n, 2k+1)(-4)^k}. - Paul Barry (pbarry(AT)wit.ie), Sep 20 2003
a(n+1)=sum{k=0..n, C(k,n-k)2^k*(-5/2)^(n-k)}; - Paul Barry (pbarry(AT)wit.ie), Mar 16 2006
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PROGRAM
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(Other) sage: [lucas_number1(n, 2, 5) for n in xrange(0, 29)] # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 23 2009]
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CROSSREFS
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Cf. A084102, A088136, A088137, A088139.
a(n)^2 = A094423(n).
Sequence in context: A151508 A164826 A055392 this_sequence A110060 A061081 A007368
Adjacent sequences: A045870 A045871 A045872 this_sequence A045874 A045875 A045876
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KEYWORD
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sign
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Paul Barry (pbarry(AT)wit.ie), Sep 20 2003
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