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%I #6 Jun 14 2019 00:28:17
%S 0,1,2,5,9,13,19,25,33,42,51,62,74,86,100,114,130,147,164,183,202,223,
%T 245,267,291,316,341,368,395,424,454,484,516,549,582,617,652,689,727,
%U 765,805,845,887,930,973,1018,1064,1110,1158,1206,1256,1307,1358,1411
%N a(n) = Sum_{k=0..n} floor(phi*floor(n/phi)) where phi = (1+sqrt(5))/2.
%F a(n) = n*(n-3)/2 + ceiling(n/phi).
%o (PARI) phi=(1+sqrt(5))/2;a(n)=n*(n-3)/2+ceil(n/phi)
%Y Cf. A120613, A120614.
%K nonn
%O 1,3
%A _Benoit Cloitre_, Jun 17 2006
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