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 A159367 #11 Jun 02 2025 01:32:27 %S A159367 4,540,18720,531300,8583300,86748088,623757696,3483871560,16023245700, %T A159367 63174296020,219752181792,688950636972,1978607887620,5271705817200, %U A159367 13162584962560,31050835145616,69671782148868,149524133455500 %N A159367 Number of n X n arrays of squares of integers summing to 7. %C A159367 All such sequences have holonomic recurrences (cf. comment in A159359). - _Georg Fischer_, Feb 17 2022 %H A159367 R. H. Hardin, <a href="/A159367/b159367.txt">Table of n, a(n) for n=2..100</a> %H A159367 <a href="/index/Rec#order_15">Index entries for linear recurrences with constant coefficients</a>, signature (15, -105, 455, -1365, 3003, -5005, 6435, -6435, 5005, -3003, 1365, -455, 105, -15, 1). %F A159367 Empirical: a(n)=n^2*(n-1)*(n+1)*(n^2-2)*(n^2-3)*(n^6-15*n^4+74*n^2+720)/5040. [From _R. J. Mathar_, Aug 11 2009] %K A159367 nonn %O A159367 2,1 %A A159367 _R. H. Hardin_ Apr 11 2009