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 A366136 #18 Jan 23 2024 11:06:01
%S A366136 0,1,1,2,2,2,1,2,2,3,3,3,2,3,3,4,3,3,2,3,3,3,2,2,1,2,2,3,3,3,2,3,3,4,
%T A366136 4,4,3,4,4,5,4,4,3,4,4,4,3,3,2,3,3,4,4,4,3,4,4,5,5,5,4,5,5,6,5,5,4,5,
%U A366136 5,5,4,4,3,4,4,5,5,5,4,5,5,6,5,5,4,5,5
%N A366136 Minimal number of factorials or their negatives that add to n.
%H A366136 Alois P. Heinz, <a href="/A366136/b366136.txt">Table of n, a(n) for n = 0..10000</a>
%e A366136 11 = 6 + 6 - 1 (three factorials), so a(11) = 3.
%e A366136 15 = 6 + 6 + 2 + 1 or 15 = 24 - 6 - 2 - 1 (four factorials), so a(15) = 4.
%t A366136 seq[m_] := Module[{s = Table[m!, {m!}], d, b, sum}, Do[d = PadLeft[Most@ IntegerDigits[k, MixedRadix[Range[m, 1, -1]]], m]; Do[b = 2*PadLeft[ IntegerDigits[i, 2], m] - 1; sum = Total[b * d * Range[m, 1, -1]!]; If[0 < sum <= m!, s[[sum]] = Min[s[[sum]], Total[d]]], {i, 1, 2^m - 1}], {k, 1, 2*m!}]; Join[{0}, s]]; seq[5] (* _Amiram Eldar_, Oct 03 2023 *)
%Y A366136 Cf. A000142, A034968, A366693.
%K A366136 nonn,look
%O A366136 0,4
%A A366136 _James C. McMahon_, Sep 30 2023