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 A046715 #21 May 19 2024 14:03:09 %S A046715 0,1,10,105,1176,13860,169884,2147145,27810640,367479684,4936848280, %T A046715 67255063876,927192688800,12914469594000,181497968832600, %U A046715 2570903476583625,36671501616314400,526348636137670500,7597019633665077000,110205019733436728100 %N A046715 Secondary root edges in doubly rooted tree maps with n edges. %H A046715 Alois P. Heinz, <a href="/A046715/b046715.txt">Table of n, a(n) for n = 0..250</a> %H A046715 R. C. Mullin, <a href="http://dx.doi.org/10.1016/S0021-9800(67)80001-2">On the average activity of a spanning tree of a rooted map</a>, J. Combin. Theory, 3 (1967), 103-121. %H A046715 R. C. Mullin, <a href="/A260039/a260039.pdf">On the average activity of a spanning tree of a rooted map</a>, J. Combin. Theory, 3 (1967), 103-121. [Annotated scanned copy] %F A046715 B(n) = (2*n)!*(2*n+2)!*n / (2*n!*(n+1)!^2*(n+2)!). - _Alois P. Heinz_, Dec 22 2011 %p A046715 B:= n-> (2*n)!*(2*n+2)!*n / (2*n!*(n+1)!^2*(n+2)!): %p A046715 seq(B(n), n=0..20); # _Alois P. Heinz_, Dec 22 2011 %K A046715 nonn,easy %O A046715 0,3 %A A046715 _N. J. A. Sloane_ %E A046715 Corrected and extended by _Alois P. Heinz_, Dec 22 2011