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 A344112 #23 Aug 24 2022 14:42:49 %S A344112 1,3,12,7,56,485,15,240,4015,65280,31,992,32525,1047552,33551307,63, %T A344112 4032,261415,16773120,1073726199,68719430080,127,16256,2094965, %U A344112 268419072,34359660243,4398046231168,562949952597769,255,65280,16770655,4294901760,1099511237151 %N A344112 Triangle read by rows: T(n,k) is the number of relations from an n-element set to a k-element set that are not functions. %H A344112 Michael De Vlieger, <a href="/A344112/b344112.txt">Table of n, a(n) for n = 1..1275</a> (rows n = 1..50, flattened) %H A344112 Mohammad K. Azarian, <a href="https://doi.org/10.12988/imf.2022.912321">Remarks and Conjectures Regarding Combinatorics of Discrete Partial Functions</a>, Int'l Math. Forum (2022) Vol. 17, No. 3, 129-141. %F A344112 T(n,k) = 2^(n*k) - k^n, n,k >= 1. %e A344112 T(2,2) = (number of relations) - (number of functions) = 2^4 - 4 = 12. %e A344112 Triangle T(n,k) begins: %e A344112 1; %e A344112 3, 12; %e A344112 7, 56, 485; %e A344112 15, 240, 4015, 65280; %e A344112 31, 992, 32525, 1047552, 33551307; %t A344112 Column[Table[2^(n*k) - k^n, {n, 10}, {k, n}], Center] %Y A344112 Cf. A101030, A199656, A036679, A344110. %K A344112 easy,nonn,tabl %O A344112 1,2 %A A344112 _Mohammad K. Azarian_, May 10 2021