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 A305023 #11 Feb 16 2025 08:33:54 %S A305023 1,3,12,34,100,246,630,1433,3298,7124,15283,31358,64100,126406,247587, %T A305023 472864,895548,1661690,3059734,5538991,9950980,17631398,31004004, %U A305023 53878023,92979904,158806852,269448833,453099946,757152246,1255180557,2068707378,3385065586 %N A305023 Number of triples (p,q,r) of partitions such that p is a partition of n and r <= q <= p (by diagram containment). %H A305023 Alois P. Heinz, <a href="/A305023/b305023.txt">Table of n, a(n) for n = 0..200</a> %H A305023 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FerrersDiagram.html">Ferrers Diagram</a> %H A305023 Wikipedia, <a href="https://en.wikipedia.org/wiki/Ferrers_diagram">Ferrers diagram</a> %e A305023 a(0) = 1: ((),(),()). %e A305023 a(1) = 3: (1,(),()), (1,1,()), (1,1,1). %e A305023 a(2) = 12: (11,(),()), (11,1,()), (11,1,1), (11,11,()), (11,11,1), (11,11,11), (2,(),()), (2,1,()), (2,1,1), (2,2,()), (2,2,1), (2,2,2). %e A305023 a(3) = 34: (111,(),()), (111,1,()), (111,1,1), (111,11,()), (111,11,1), (111,11,11), (111,111,()), (111,111,1), (111,111,11), (111,111,111), (21,(),()), (21,1,()), (21,1,1), (21,11,()), (21,11,1), (21,11,11), (21,2,()), (21,2,1), (21,2,2), (21,21,()), (21,21,1), (21,21,11), (21,21,2), (21,21,21), (3,(),()), (3,1,()), (3,1,1), (3,2,()), (3,2,1), (3,2,2), (3,3,()), (3,3,1), (3,3,2), (3,3,3). %Y A305023 Cf. A000041, A297388. %K A305023 nonn %O A305023 0,2 %A A305023 _Alois P. Heinz_, May 23 2018