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 A308826 #10 Sep 13 2019 09:41:27
%S A308826 0,0,0,0,0,1,1,3,5,10,15,25,35,54,74,105,138,189,242,317,400,509,628,
%T A308826 783,950,1164,1394,1677,1985,2361,2765,3246,3768,4382,5043,5815,6640,
%U A308826 7596,8621,9789,11043,12465,13981,15689,17513,19554,21723,24139,26704
%N A308826 Sum of the second largest parts in the partitions of n into 5 parts.
%H A308826 <a href="/index/Par#part">Index entries for sequences related to partitions</a>
%F A308826 a(n) = Sum_{l=1..floor(n/5)} Sum_{k=l..floor((n-l)/4)} Sum_{j=k..floor((n-k-l)/3)} Sum_{i=j..floor((n-j-k-l)/2)} i.
%F A308826 a(n) = A308822(n) - A308823(n) - A308824(n) - A308825(n) - A308827(n).
%e A308826 The partitions of n into 5 parts for n = 10, 11, ..
%e A308826 1+1+1+1+10
%e A308826 1+1+1+2+9
%e A308826 1+1+1+3+8
%e A308826 1+1+1+4+7
%e A308826 1+1+1+5+6
%e A308826 1+1+1+1+9 1+1+2+2+8
%e A308826 1+1+1+2+8 1+1+2+3+7
%e A308826 1+1+1+3+7 1+1+2+4+6
%e A308826 1+1+1+4+6 1+1+2+5+5
%e A308826 1+1+1+5+5 1+1+3+3+6
%e A308826 1+1+1+1+8 1+1+2+2+7 1+1+3+4+5
%e A308826 1+1+1+2+7 1+1+2+3+6 1+1+4+4+4
%e A308826 1+1+1+3+6 1+1+2+4+5 1+2+2+2+7
%e A308826 1+1+1+1+7 1+1+1+4+5 1+1+3+3+5 1+2+2+3+6
%e A308826 1+1+1+2+6 1+1+2+2+6 1+1+3+4+4 1+2+2+4+5
%e A308826 1+1+1+3+5 1+1+2+3+5 1+2+2+2+6 1+2+3+3+5
%e A308826 1+1+1+1+6 1+1+1+4+4 1+1+2+4+4 1+2+2+3+5 1+2+3+4+4
%e A308826 1+1+1+2+5 1+1+2+2+5 1+1+3+3+4 1+2+2+4+4 1+3+3+3+4
%e A308826 1+1+1+3+4 1+1+2+3+4 1+2+2+2+5 1+2+3+3+4 2+2+2+2+6
%e A308826 1+1+2+2+4 1+1+3+3+3 1+2+2+3+4 1+3+3+3+3 2+2+2+3+5
%e A308826 1+1+2+3+3 1+2+2+2+4 1+2+3+3+3 2+2+2+2+5 2+2+2+4+4
%e A308826 1+2+2+2+3 1+2+2+3+3 2+2+2+2+4 2+2+2+3+4 2+2+3+3+4
%e A308826 2+2+2+2+2 2+2+2+2+3 2+2+2+3+3 2+2+3+3+3 2+3+3+3+3
%e A308826 --------------------------------------------------------------------------
%e A308826 n | 10 11 12 13 14 ...
%e A308826 --------------------------------------------------------------------------
%e A308826 a(n) | 15 25 35 54 74 ...
%e A308826 --------------------------------------------------------------------------
%e A308826 - _Wesley Ivan Hurt_, Sep 12 2019
%t A308826 Table[Sum[Sum[Sum[Sum[i, {i, j, Floor[(n - j - k - l)/2]}], {j, k, Floor[(n - k - l)/3]}], {k, l, Floor[(n - l)/4]}], {l, Floor[n/5]}], {n, 0, 100}]
%Y A308826 Cf. A026811, A308822, A308823, A308824, A308825, A308827.
%K A308826 nonn
%O A308826 0,8
%A A308826 _Wesley Ivan Hurt_, Jun 26 2019