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 A037291 #37 Feb 02 2023 15:29:09 %S A037291 1,1,1,4,1,1,1,11,4,1,1,4,1,1,1,50,1,4,1,4,1,1,1,11,4,1,12,4,1,1,1, %T A037291 208,1,1,1,16,1,1,1,11,1,1,1,4,4,1,1,50,4,4,1,4,1,12,1,11,1,1,1,4,1,1, %U A037291 4 %N A037291 Number of rings with 1 containing n elements. %C A037291 Many authors simply call these "rings". They are also known as unital rings, rings with unity, or rings with identity. - _Charles R Greathouse IV_, Aug 12 2015 %C A037291 Is this sequence multiplicative? That is, if p and q are distinct primes, is it true that a(p^i*q^j) = a(p^i)*a(q^j)? - _Jianing Song_, Oct 26 2019. The answer is yes - see the Eric M. Rains link. - _N. J. A. Sloane_, Oct 27 2019 %H A037291 Gérard P. Michon, <a href="https://www.numericana.com/answer/rings.htm">Ring Theory</a>, Numericana, 2000-2022. %H A037291 C. Noebauer, <a href="https://web.archive.org/web/20080111141811/http://www.algebra.uni-linz.ac.at/~noebsi/">Home page</a> and <a href="https://web.archive.org/web/20061002201537/http://www.algebra.uni-linz.ac.at/~noebsi/ringtable.html">Table of numbers of small rings</a> [Archived copies] %H A037291 Eric M. Rains, <a href="/A037291/a037291.txt">The number of unital rings with n elements is a multiplicative function of n</a>. %Y A037291 Cf. A027623, A037221, A127707. %K A037291 nonn,nice,hard,mult %O A037291 1,4 %A A037291 _Christian G. Bower_, Jun 15 1998 %E A037291 a(16) and a(32)-a(63) from Christof Noebauer (christof.noebauer(AT)algebra.uni-linz.ac.at), Sep 29 2000 %E A037291 Keyword 'mult' added by _Jianing Song_, Feb 02 2020 %E A037291 a(54) corrected by _Andrey Zabolotskiy_, Feb 02 2023