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 A281872 #11 Mar 25 2017 20:41:40
%S A281872 1,1,1,3,8,24,74,238,786,2646,9071,31536,110967,394420,1414053,
%T A281872 5107523,18568628,67894564,249513890,921134164,3414439996,12703212213,
%U A281872 47419589969,177551521838,666655929561,2509526456940,9469082269965,35807434636137,135681047696427
%N A281872 Number of sets of exactly n positive integers <= 2n having a square element sum.
%H A281872 Alois P. Heinz, <a href="/A281872/b281872.txt">Table of n, a(n) for n = 0..130</a>
%F A281872 a(n) = A281871(2n,n).
%e A281872 a(0) = 1: {}.
%e A281872 a(1) = 1: {1}.
%e A281872 a(2) = 1: {1,3}.
%e A281872 a(3) = 3: {1,2,6}, {1,3,5}, {2,3,4}.
%e A281872 a(4) = 8: {1,2,5,8}, {1,2,6,7}, {1,3,4,8}, {1,3,5,7}, {1,4,5,6}, {2,3,4,7}, {2,3,5,6}, {4,6,7,8}.
%Y A281872 Cf. A281871, A284251.
%K A281872 nonn
%O A281872 0,4
%A A281872 _Alois P. Heinz_, Jan 31 2017