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 A026866 #13 Nov 22 2023 21:37:00 %S A026866 1,6,29,132,589,2613,11592,51558,230181,1032060,4648150,21027765, %T A026866 95542878,435939525,1997076805,9183661080,42383777344,196271453865, %U A026866 911804206063,4248637465050,19852810349837,93012949698861,436860932671829 %N A026866 a(n) = T(2n+1,n+2), T given by A026747. %C A026866 This appears to obey a hypergeometric 8-term recurrence with 4th-order polynomial coefficients. - _R. J. Mathar_, Nov 10 2013 %Y A026866 Cf. A026747. %K A026866 nonn %O A026866 1,2 %A A026866 _Clark Kimberling_