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 A185016 #30 Jun 19 2024 09:14:26 %S A185016 0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %T A185016 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, %U A185016 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 %N A185016 Characteristic function of 6. %C A185016 Number of connected 2-regular (simple) graphs with girth exactly 6. %C A185016 The Euler transformation of this sequence is A079979. %H A185016 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1). %F A185016 a(n) = A185116(n) - A185117(n). %o A185016 (Python) %o A185016 def A185016(n): return int(n==6) # _Chai Wah Wu_, Feb 04 2022 %Y A185016 Characteristic function of g: A000007 (g=0), A063524 (g=1), A185012 (g=2), A185013 (g=3), A185014 (g=4), A185015 (g=5), this sequence (g=6), A185017 (g=7). %K A185016 nonn,easy %O A185016 0,1 %A A185016 _Jason Kimberley_, Sep 30 2011