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 A261421 #11 Oct 24 2022 15:12:00 %S A261421 1,1,7,25,427,1911,18051,87945,3518515,17943211,185961113,976288495, %T A261421 20727407743,111039591475,1199227922235,6520801221225,570761912807235, %U A261421 3139190488028595,34696316039725725,192564553799569875,4291438629174301605,23993043241870766505,269139354637637831685 %N A261421 Numerators of coefficients in Taylor series expansion of sqrt(m(x)) where m(x) is g.f. for Motzkin numbers A001006. %e A261421 The coefficients are [1, 1/2, 7/8, 25/16, 427/128, 1911/256, 18051/1024, 87945/2048, 3518515/32768, 17943211/65536, 185961113/262144, 976288495/524288, 20727407743/4194304, 111039591475/8388608, 1199227922235/33554432, 6520801221225/67108864, ... %Y A261421 The denominators appear to be A046161. Cf. A001006. %K A261421 sign,frac %O A261421 0,3 %A A261421 _N. J. A. Sloane_, Aug 27 2015 %E A261421 Name corrected by Werner Schulte, Oct 24 2022