This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A368642 #4 Jan 01 2024 23:26:27
%S A368642 1,3,6,8,11,14,19,21,23,26,31,33,38,41,46,50,53,55,60,62,67,72,77,79,
%T A368642 83,86,90,92,97,100,109,111,114,119,124,128,133,136,141,145,150,153,
%U A368642 162,164,168,173,178,180,184,186,191,195,200,202,207,211,216,221,226,228
%N A368642 a(n) = Sum_{k=1..n} mu(k)^2 * ceiling(n/k), where mu is the Möbius function (A008683).
%F A368642 a(n) = A013928(n) + A008966(n) + A064608(n) - A034444(n).
%t A368642 Table[Sum[MoebiusMu[k]^2*Ceiling[n/k], {k, n}], {n, 100}]
%Y A368642 Cf. A008683 (mu), A008966, A013928, A034444, A064608.
%K A368642 nonn,easy
%O A368642 1,2
%A A368642 _Wesley Ivan Hurt_, Jan 01 2024