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 A376572 #12 Sep 29 2024 06:25:08
%S A376572 1,2,1,4,3,2,10,9,8,6,32,33,31,31,26
%N A376572 Triangle read by rows: T(n,k) is the frequency of the symbol k in the lexicographically earliest minimal superpermutation on n symbols, where the symbols are {1, 2, ..., n}.
%C A376572 Equivalently, T(n,k) is the frequency of k in row n of A332089 (see there for more information).
%H A376572 Michael Engen and Vincent Vatter, <a href="https://doi.org/10.1080/00029890.2021.1835384">Containing All Permutations</a>, The American Mathematical Monthly, 128 (1), 2021, pp. 4-24 (<a href="https://doi.org/10.48550/arXiv.1810.08252">preprint version</a>).
%H A376572 Wikipedia, <a href="https://en.wikipedia.org/wiki/Superpermutation">Superpermutation</a>.
%e A376572 Triangle begins:
%e A376572 n\k| 1 2 3 4 5 ...
%e A376572 ----------------------------
%e A376572 1 | 1;
%e A376572 2 | 2, 1;
%e A376572 3 | 4, 3, 2;
%e A376572 4 | 10, 9, 8, 6;
%e A376572 5 | 32, 33, 31, 31, 26;
%e A376572 ...
%e A376572 For n = 3, the minimal superpermutation is 123121321; symbol 1 appears 4 times, symbol 2 appears 3 times and symbol 3 appears 2 times.
%Y A376572 Cf. A180632 (row sums, for n >= 1), A332089.
%K A376572 nonn,tabl,hard,more
%O A376572 1,2
%A A376572 _Paolo Xausa_, Sep 28 2024