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 A066295 #16 Mar 23 2024 19:47:14 %S A066295 1,1,1,2,1,0,1,1,2,0,1,-1,1,0,1,-4,1,-1,1,-1,0,0,1,-9,2,0,1,0,1,-2,1, %T A066295 -37,1,0,1,-6,1,0,0,-8,1,-4,1,0,2,0,1,-42,2,-1,1,-1,1,-9,0,-7,0,0,1, %U A066295 -9,1,0,0,-245,1,-2,1,-1,1,-2,1,-38,1,0,1,0,1,-4,1,-42,-5,0,1,-11,1,0,1,-6,1,-6,1,0,0 %N A066295 Number of Abelian groups of order n minus the number of non-Abelian groups of order n. %H A066295 T. D. Noe, <a href="/A066295/b066295.txt">Table of n, a(n) for n = 1..2015</a> [a(1024) corrected by Andrey Zabolotskiy] %F A066295 a(n) = A000688(n) - A060689(n). %t A066295 a[n_] := 2 FiniteAbelianGroupCount[n] - FiniteGroupCount[n]; %t A066295 a /@ Range[100] (* _Jean-François Alcover_, Jan 01 2020 *) %Y A066295 Cf. A000688, A060689, A000001. %K A066295 sign %O A066295 1,4 %A A066295 Sharon Sela (sharonsela(AT)hotmail.com), Jan 01 2002 %E A066295 Edited by _Dean Hickerson_, Mar 04 2002 %E A066295 More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 05 2003