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A110532 a(n) = floor(n/2) + floor(n/5). 6

%I

%S 0,0,1,1,2,3,4,4,5,5,7,7,8,8,9,10,11,11,12,12,14,14,15,15,16,17,18,18,

%T 19,19,21,21,22,22,23,24,25,25,26,26,28,28,29,29,30,31,32,32,33,33,35,

%U 35,36,36,37,38,39,39,40,40,42,42,43,43,44,45,46,46,47,47,49,49,50,50

%N a(n) = floor(n/2) + floor(n/5).

%H G. C. Greubel, <a href="/A110532/b110532.txt">Table of n, a(n) for n = 0..5000</a>

%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (0,1,0,0,1,0,-1).

%F a(n) = A004526(n) + A002266(n).

%F G.f.: x^2*(1+x+x^2+2*x^3+2*x^4) / ( (1+x)*(x^4+x^3+x^2+x+1)*(x-1)^2 ). - _R. J. Mathar_, Feb 20 2011

%F a(n) = 7n/10 + O(1). - _Charles R Greathouse IV_, Jun 11 2015

%t Table[Floor[n/2]+Floor[n/5],{n,0,80}] (* or *) LinearRecurrence[ {0,1,0,0,1,0,-1},{0,0,1,1,2,3,4},80] (* _Harvey P. Dale_, Dec 26 2015 *)

%o (PARI) a(n)=n\2 + n\5 \\ _Charles R Greathouse IV_, Jun 11 2015

%Y Cf. A010761, A110533.

%K nonn,easy

%O 0,5

%A _Reinhard Zumkeller_, Jul 25 2005

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Last modified March 1 03:09 EST 2021. Contains 341732 sequences. (Running on oeis4.)