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 A003971 #25 Dec 06 2022 07:56:39 %S A003971 1,2,3,3,4,6,5,4,7,8,7,9,8,10,12,5,10,14,11,12,15,14,13,12,13,16,15, %T A003971 15,16,24,17,6,21,20,20,21,20,22,24,16,22,30,23,21,28,26,25,15,21,26, %U A003971 30,24,28,30,28,20,33,32,31,36,32,34,35,7,32,42,35,30,39,40,37,28,38,40 %N A003971 Inverse Möbius transform of A003960. %H A003971 Amiram Eldar, <a href="/A003971/b003971.txt">Table of n, a(n) for n = 1..10000</a> %H A003971 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>. %F A003971 Multiplicative with a(p^e) = e+1 if p = 2; (((p+1)/2)^(e+1) - 1)/((p-1)/2) if p > 2. - _David W. Wilson_, Sep 01 2001 %t A003971 f[p_, e_] := (((p + 1)/2)^(e + 1) - 1)/((p - 1)/2); f[2, e_] := e + 1; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* _Amiram Eldar_, Dec 06 2022 *) %Y A003971 Cf. A003960. %K A003971 nonn,easy,mult %O A003971 1,2 %A A003971 _Marc LeBrun_ %E A003971 More terms from _Reiner Martin_, Aug 15 2001 %E A003971 Formula corrected by _Sean A. Irvine_, Sep 26 2015