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 A347846 #16 Jun 27 2025 09:38:03
%S A347846 1,1,11,1093,979163,7895396653,572984959186643,374244678702477629605,
%T A347846 2199939020346263706461674955,116387990444553949414146511586296381,
%U A347846 55417662962428710787068813831544886356769891,237482030708312867514661156730660313316831290472695733
%N A347846 a(n) is the number of (strict) chains of subspaces with ends 0 and (F_9)^n.
%H A347846 Alois P. Heinz, <a href="/A347846/b347846.txt">Table of n, a(n) for n = 0..46</a> (terms n = 1..40 from Álvar Ibeas)
%F A347846 a(n) = Sum_{L partition of n} A347491(n, L) * A036038(len(L), sig(L)), where sig(L) is the partition composed by the part multiplicities of L.
%e A347846 a(3) = 1093 = 1 * 1 + 91 * 2 + 910 * 1, counting:
%e A347846 the unrefined chain 0 < (F_9)^3;
%e A347846 91 chains 0 < V < (F_9)^3, with dim(V) = 1; another
%e A347846 91 chains 0 < V < (F_9)^3, with dim(V) = 2; and
%e A347846 910 chains 0 < V_1 < V_2 < (F_9)^3.
%Y A347846 Cf. A289545, A347491, A036038, A381299.
%Y A347846 Column k=9 of A381426.
%K A347846 nonn
%O A347846 0,3
%A A347846 _Álvar Ibeas_, Sep 15 2021
%E A347846 a(0)=1 prepended by _Alois P. Heinz_, Jun 25 2025