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 A079920 #14 Dec 03 2021 17:06:25 %S A079920 1,16,6746,313464,9479292,174763208,2262089361,22088730348, %T A079920 171764779170,1106667645872,6087616677864,29267369636800, %U A079920 125299076209408,485013257865472,1718947213795328,5636819806209792,17235204961273600,49467590616190208,134058587073795072,344809293460572928,845577589114049792,1985060631106310400 %N A079920 Solution to the Dancing School Problem with 15 girls and n+15 boys: f(15,n). %C A079920 f(g,h) = per(B), the permanent of the (0,1)-matrix B of size g X g+h with b(i,j)=1 if and only if i <= j <= i+h. See A079908 for more information. %C A079920 For fixed g, f(g,n) is polynomial in n for n >= g-2. See reference. %H A079920 Jaap Spies, <a href="http://www.nieuwarchief.nl/serie5/pdf/naw5-2006-07-4-283.pdf">Dancing School Problems</a>, Nieuw Archief voor Wiskunde 5/7 nr. 4, Dec 2006, pp. 283-285. %H A079920 Jaap Spies, <a href="http://www.jaapspies.nl/mathfiles/dancingschool.pdf">Dancing School Problems, Permanent solutions of Problem 29</a>. %H A079920 Jaap Spies, <a href="http://www.jaapspies.nl/mathfiles/dancing.sage">Sage program "dance" for computing the polynomial a(n)</a>. %F A079920 a(n) = n^15 - 90*n^14 + 4200*n^13 - 131040*n^12 + 3011190*n^11 - 53441388*n^10 + 751250500*n^9 - 8470570680*n^8 + 76896261585*n^7 - 560015385930*n^6 + 3235452199980*n^5 - 14525684311320*n^4 + 48947506506080*n^3 - 116650912956480*n^2 + 175512302620800*n - 125495209214208 for n >= 13. - _Georg Fischer_, Apr 27 2021 (polynomial computed by the program in links) %Y A079920 Cf. A079908-A079928. %K A079920 nonn,easy %O A079920 0,2 %A A079920 _Jaap Spies_, Jan 28 2003 %E A079920 Corrected by _Jaap Spies_, Feb 01 2004 %E A079920 a(12)-a(21) from _Georg Fischer_, Apr 27 2021