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 A170947 #23 Jan 27 2025 14:45:54 %S A170947 2,5,20,85,418,2242,12828,77777,493286,3260485,22314484,157735801, %T A170947 1147285362,8570960234,65611620808,513963377327,4113363020482, %U A170947 33598074760393,279764563749076,2372822051513583,20481425601917742,179795508212739402,1604084463778300348,14536376462636666141 %N A170947 Number of achiral combinatorial maps with n edges. %C A170947 Achiral maps are also called reflexible. %H A170947 Antonio Breda d'Azevedo, Alexander Mednykh, and Roman Nedela, <a href="/A170947/b170947.txt">Table of n, a(n) for n = 1..30</a> %H A170947 Antonio Breda d'Azevedo, Alexander Mednykh, and Roman Nedela, <a href="https://doi.org/10.1016/j.disc.2009.11.017">Enumeration of maps regardless of genus: Geometric approach</a>, Discrete Mathematics, Volume 310, 2010, Pages 1184-1203. %Y A170947 Row sums of A380234. %Y A170947 Cf. A170946 (sensed), A170948 (chiral pairs), A214816 (unsensed). %K A170947 nonn %O A170947 1,1 %A A170947 _N. J. A. Sloane_, Feb 21 2010