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 A120380 #22 Sep 30 2024 10:50:29
%S A120380 1,2,11,77,627,5604,53174,526823,5392783,56634173,607163746,
%T A120380 6620830889,73232243759,819876908323,9275102575355,105882246722733,
%U A120380 1218374349844333,14118662665280005,164637479165761044,1930656072350465812,22755290216580025259,269435605212954994471
%N A120380 Number of partitions of n*(n+1).
%H A120380 Henry Bottomley, <a href="http://www.se16.info/js/partitions.htm">Partition and composition calculator</a>.
%H A120380 G. P. Michon, <a href="http://numericana.com/data/partition.htm">Partition Function</a>
%F A120380 a(n) = A000041(A002378(n)). - _Michel Marcus_, Sep 30 2024
%e A120380 a(2)=11 because the number of partitions of 6 is 11.
%p A120380 with(combinat); [seq(numbpart(n*(n+1)),n=1..20)];
%p A120380 with(combinat): seq(numbpart(n*(n+1)),n=0..21);
%t A120380 Table[PartitionsP[n*(n+1)],{n,0,21}] (* _James C. McMahon_, Sep 30 2024 *)
%o A120380 (PARI) a(n)=numbpart(n^2+n) /* _Michael Somos_, Jul 24 2006 */
%Y A120380 Cf. A000041, A003107, A002378.
%K A120380 nonn
%O A120380 0,2
%A A120380 _Zerinvary Lajos_, Jun 29 2006
%E A120380 Edited by _Michael Somos_, _Emeric Deutsch_ and _N. J. A. Sloane_, Jul 23 2006