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 A210766 #22 Dec 27 2024 09:51:33 %S A210766 1,13,141,1204,7570,36021,136948,436696,1212399,3013165,6843991, %T A210766 14431308,28591576,53726869,96473910,166535536,277726093,449264781, %U A210766 707353489,1087078180 %N A210766 Number of 8-hoops with n symbols and no a-rooted trees. %H A210766 S. G. Williamson, <a href="http://dx.doi.org/10.1016/0012-365X(72)90043-X">The combinatorial analysis of patterns and the principle of inclusion-exclusion</a>, Discrete Math. 1 (1972), no. 4, 357--388. MR0299493 (45 #8541). %H A210766 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (9, -36, 84, -126, 126, -84, 36, -9, 1). %F A210766 G.f.: x*(1+x)*(1+3*x+57*x^2+262*x^3+582*x^4+321*x^5+34*x^6)/(1-x)^9. [_Colin Barker_, Apr 17 2012] %p A210766 A210766 := proc(n) %p A210766 (n^8-8*n^7+36*n^6-92*n^5+155*n^4-148*n^3 +88*n^2-16*n)/16 ; %p A210766 end proc: # _R. J. Mathar_, Mar 27 2012 %Y A210766 Cf. A060560, A210768, A295925. %K A210766 nonn,easy %O A210766 1,2 %A A210766 _N. J. A. Sloane_, Mar 25 2012