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 A280251 #21 Apr 22 2023 13:25:46
%S A280251 1,5,8,18,12,34,31,63,56,88,83,129,91,138,103,195,173,303,199,345,256,
%T A280251 442,274,482,294,525,410,539,487,668,517,714,539,913,675,1150,776,
%U A280251 1131,755,1223,783,1406,898,1551,1163,1605,1191,1774,1271,1875,1378,2031,1521,2547
%N A280251 Sum of the larger parts of the partitions of 2n into two squarefree parts.
%H A280251 <a href="/index/Par#part">Index entries for sequences related to partitions</a>
%F A280251 a(n) = Sum_{i=1..n} (2*n-i) * mu(i)^2 * mu(2*n-i)^2, where mu is the Möbius function (A008683).
%F A280251 a(n) = A280252(n) - A280250(n).
%p A280251 with(numtheory): A280251:=n->sum((2*n-i)*mobius(i)^2*mobius(2*n-i)^2, i=1..n): seq(A280251(n), n=1..100);
%t A280251 Table[Total[Select[IntegerPartitions[2 n,{2}],AllTrue[#,SquareFreeQ]&][[;;,1]]],{n,60}] (* _Harvey P. Dale_, Apr 22 2023 *)
%Y A280251 Cf. A008683, A187129, A280226, A280250, A280252.
%K A280251 nonn,easy
%O A280251 1,2
%A A280251 _Wesley Ivan Hurt_, Dec 29 2016