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%I #26 Mar 21 2020 11:44:50
%S 1,1,2,2,3,4,5,6,7,9,10,12,13,16,17,20,21,25,26,30,31,36,37,42,43,49,
%T 50,56,57,64,65,72,73,81,82,90,91,100,101,110,111,121,122,132,133,144,
%U 145,156,157,169,170
%N a(n) = a(n-1) - [a(n-1)/2] + a(n-2) - [a(n-5)/2] where [k] = floor(k).
%H Chai Wah Wu, <a href="/A173151/b173151.txt">Table of n, a(n) for n = 0..10000</a>
%F a(n) = a(n-1)-floor[a(n-1)/2]+a(n-2)-floor[a(n-5)/2].
%F From _Chai Wah Wu_, Jun 02 2016: (Start)
%F a(n) = a(n-1) + a(n-2) - a(n-3) + a(n-4) - a(n-5) - a(n-6) + a(n-7) for n > 6.
%F G.f.: (-x^5 + x^4 - 1)/((x - 1)^3*(x + 1)^2*(x^2 + 1)). (End)
%F a(n) = ((-1)^n*(11 - 2*n) + 2*n*(n + 5) + 4*sin(Pi*n/2) - 4*cos(Pi*n/2) + 25)/32. - _Ilya Gutkovskiy_, Jun 03 2016
%t f[-3] = 0; f[-2] = 0; f[-1] = 0; f[0] = 1; f[1] = 1;
%t f[n_] := f[n] = f[n - 1] + f[n - 2] - Floor[f[n - 1]/2] - Floor[f[n - 5]/2]
%t Table[f[n], {n, 0, 50}]
%K nonn
%O 0,3
%A _Roger L. Bagula_, Nov 22 2010
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