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A111466
a(1) = 1, a(n+1) = a(n) - F(n+1), if F(n+1) <= a(n), else a(n+1) = a(n) + F(n+1). F(n) is the n-th Fibonacci number (A000045).
3
1, 0, 2, 5, 0, 8, 21, 0, 34, 89, 0, 144, 377, 0, 610, 1597, 0, 2584, 6765, 0, 10946, 28657, 0, 46368, 121393, 0, 196418, 514229, 0, 832040, 2178309, 0, 3524578, 9227465, 0, 14930352, 39088169, 0, 63245986, 165580141, 0, 267914296, 701408733, 0, 1134903170
OFFSET
1,3
FORMULA
a(3n+2) =0, a(3n) = F(3n), a(3n+1) = F(3n+2).
G.f.: -x*(1+2*x^2+x^3) / ( (x^2+x-1)*(x^4-x^3+2*x^2+x+1) ). - R. J. Mathar, Jun 23 2014
MAPLE
with(combinat): a[1]:=1: for n from 1 to 50 do if fibonacci(n+1)<=a[n] then a[n+1]:=a[n]-fibonacci(n+1) else a[n+1]:=a[n]+fibonacci(n+1) fi od: seq(a[n], n=1..51); # Emeric Deutsch, Aug 11 2005
MATHEMATICA
nxt[{n_, a_}]:=Module[{fib=Fibonacci[n+1]}, {n+1, If[fib<=a, a-fib, a+fib]}]; Transpose[NestList[nxt, {1, 1}, 50]][[2]] (* Harvey P. Dale, Nov 21 2012 *)
CROSSREFS
Sequence in context: A265299 A020836 A349353 * A308715 A201745 A192042
KEYWORD
easy,nonn
AUTHOR
Amarnath Murthy, Aug 05 2005
EXTENSIONS
More terms from Emeric Deutsch, Aug 11 2005
STATUS
approved