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 A090541 a(n) = floor((Sum_{r=1..n} r)*(Sum_{r=1..n} 1/r)). 0

%I

%S 1,4,11,20,34,51,72,97,127,161,199,242,289,341,398,459,526,597,674,

%T 755,842,933,1030,1132,1240,1352,1470,1594,1723,1857,1997,2142,2293,

%U 2450,2612,2780,2953,3132,3317,3508,3704,3907,4115,4328,4548,4774,5006,5243

%N a(n) = floor((Sum_{r=1..n} r)*(Sum_{r=1..n} 1/r)).

%C For large n, a(n) = floor(n*(n+1)/2)*(log(n) + 0.5772...,(Euler's constant)).

%p a:=n->floor(sum(k,k=1..n)*sum(1/k,k=1..n)):seq(a(n),n=1..56); # _Emeric Deutsch_, Apr 18 2005

%o (PARI) a(n) = floor((n*(n+1)/2)*sum(k=1, n, 1/k)); \\ _Michel Marcus_, Aug 18 2019

%Y Cf. A052488.

%K nonn

%O 1,2

%A _Amarnath Murthy_, Dec 09 2003

%E More terms from _Emeric Deutsch_, Apr 18 2005

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Last modified December 1 22:24 EST 2020. Contains 338858 sequences. (Running on oeis4.)