A077025 - OEIS

%I #9 Jan 03 2024 06:31:52

%S 0,1,3,4,7,9,11,14,17,19,23,25,28,32,36,37,41,46,48,52,56,58,64,66,70,

%T 74,78,82,86,90,92,97,103,105,111,114,116,122,128,130,135,139,143,147,

%U 153,157,161,165,168,175,179,181,189,193,197,201,205,209,215,221,224

%N a(n) = Sum_{k=1..n} floor(n/(k + 1/2)).

%C It appears that A077024(n) - a(n) = n.

%e [4/(1 + 1/2)] + [4/(2 + 1/2)] + [4/(3 + 1/2)] + [4/(4 + 1/2)] = 2+1+1+0 = 4 = a(4).

%o (PARI) a(n) = sum(k=1, n, n\(k+1/2)); \\ _Michel Marcus_, Jan 14 2023

%Y Cf. A077024.

%K nonn

%O 1,3

%A _Clark Kimberling_, Oct 18 2002