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 A076369 #15 Apr 09 2025 04:19:09 %S A076369 2,1,2,4,4,7,6,8,9,11,10,12,12,15,16,16,16,18,18,20,22,23,22,24,25,27, %T A076369 27,28,28,29,30,32,34,35,36,36,36,39,40,40,40,41,42,44,45,47,46,48,49, %U A076369 50,52,52,52,54,56,56,58,59,58,60,60,63,63,64,66,65,66,68,70,69,70,72 %N A076369 a(n) = n + mu(n), where mu is the Moebius function (A008683). %H A076369 Amiram Eldar, <a href="/A076369/b076369.txt">Table of n, a(n) for n = 1..10000</a> %F A076369 a(n) = n + mu(m) = A000027(n) + A008683(n). %F A076369 a(n) = n iff n is not squarefree: a(A013929(k)) = A013929(k) and a(A005117(k)) <> A005117(k). %t A076369 a[n_] := n + MoebiusMu[n]; Array[a, 100] (* _Amiram Eldar_, Apr 09 2025 *) %o A076369 (PARI) a(n) = n + moebius(n); \\ _Amiram Eldar_, Apr 09 2025 %Y A076369 Cf. A000027, A005117, A008683, A013929, A063015, A076840. %K A076369 nonn,easy %O A076369 1,1 %A A076369 _Reinhard Zumkeller_ and _Labos Elemer_, Oct 14 2002