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Search: id:A074331
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| A074331 |
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a(n) = F(n+1)-(1+(-1)^n)/2. |
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+0
11
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| 0, 1, 1, 3, 4, 8, 12, 21, 33, 55, 88, 144, 232, 377, 609, 987, 1596, 2584, 4180, 6765, 10945, 17711, 28656, 46368, 75024, 121393, 196417, 317811, 514228, 832040, 1346268, 2178309, 3524577, 5702887, 9227464, 14930352, 24157816, 39088169
(list; graph; listen)
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OFFSET
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0,4
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COMMENT
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a(n) is the convolution of F(n) with the sequence (1,0,1,0,1,0,...)
Transform of F(n) under the Riordan array (1/(1-x^2),x). - Paul Barry (pbarry(AT)wit.ie), Apr 16 2005
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FORMULA
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a(n)= Sum (F(2i+e),(i=0,1,..,Floor(n/2))), where F(n) are Fibonacci numbers and e=2(n/2 - Floor(n/2)).
a(n)=a(n-1)+2a(n-2)-a(n-3)-a(n-4), a(0)=0, a(1)=1, a(2)=1, a(3)=3. G.f.: x/(1-x-2x^2+x^3+x^4)
a(2n+1)=F(2n+2), a(2n)=F(2n+1)-1.
a(n-1)=sum{k=0..floor(n/2), binomial(n-k, k-1)} - Paul Barry (pbarry(AT)wit.ie), Jul 07 2004
a(n)=sum{k=0..floor((n-1)/2), F(n-2k)}; - Paul Barry (pbarry(AT)wit.ie), Apr 16 2005
a(n)=sum{k=0..n, F(k)*(1-(-1)^floor((n+k-1)/2))}; - Paul Barry (pbarry(AT)wit.ie), Apr 16 2005
a(n) =fibonacci(n-1)+a(n-2), a(2)=1. - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 17 2008
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MAPLE
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with (combinat):a[2]:=1:for n from 2 to 50 do a[n]:=fibonacci(n-1)+a[n-2] od: seq(a[n], n=1..39); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 17 2008
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MATHEMATICA
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CoefficientList[Series[x/(1-x-2*x^2+x^3+x^4), {x, 0, 40}], x]
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PROGRAM
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(PARI) a(n)=if(n<0, 0, fibonacci(n+1)-(n+1)%2)
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CROSSREFS
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Essentially the same as A052952.
Sequence in context: A145722 A147622 A052952 this_sequence A153339 A033955 A049720
Adjacent sequences: A074328 A074329 A074330 this_sequence A074332 A074333 A074334
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KEYWORD
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easy,nonn
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AUTHOR
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Mario Catalani (mario.catalani(AT)unito.it), Aug 21 2002
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