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 A334144 #23 May 08 2020 23:21:01 %S A334144 1,1,1,1,1,2,2,1,2,2,2,2,2,2,3,1,1,2,2,2,3,2,2,2,2,2,2,3,3,3,3,1,4,2, %T A334144 4,3,3,3,3,2,2,4,4,3,4,3,3,2,4,2,3,3,3,3,3,3,3,3,3,4,4,4,4,1,5,5,5,2, %U A334144 5,5,5,3,3,3,4,3,6,4,4,2,3,2,2,4,3,4,4,3,3,5,5,3,5,3,5,2,2,4,6,3,3,3,3,3,6,3 %N A334144 Consider the mapping k -> (k - (k/p)), where prime p | k. a(n) = maximum distinct terms at any position j among the various paths to 1. %C A334144 Let i = A064097(n) be the common path length and let 1 <= j <= i. Given a path P, we find for any j relatively few distinct values. Regarding a common path length i, see A333123 comment 2, and proof at A064097. %C A334144 Maximum term in row n of A334184. %H A334144 Peter Kagey, <a href="/A334144/b334144.txt">Table of n, a(n) for n = 1..10000</a> %H A334144 Peter Kagey, Math.StackExchange, <a href="https://math.stackexchange.com/questions/3632156/does-a-graded-poset-on-mathbbn-0-generated-from-subtracting-factors-defi">Does a graded poset on the positive integers generated from subtracting factors define a lattice?</a> %H A334144 Richard Stanley, <a href="https://ocw.mit.edu/courses/mathematics/18-318-topics-in-algebraic-combinatorics-spring-2006/lecture-notes/sperner.pdf">MIT OpenCourseWare, Lecture Notes in Algebraic Combinatorics: The Sperner Property</a> %H A334144 Wikipedia, <a href="https://en.wikipedia.org/wiki/Sperner_property_of_a_partially_ordered_set">Sperner property of a partially ordered set</a> %e A334144 For n=15, the paths are shown vertically at left, and the graph obtained appears at right: %e A334144 15 15 15 15 15 => 15 %e A334144 | | | | | _/ \_ %e A334144 | | | | | / \ %e A334144 10 10 12 12 12 => 10 12 %e A334144 | | | | | | \_ _/ | %e A334144 | | | | | | \ / | %e A334144 5 8 6 6 8 => 5 8 6 %e A334144 | | | | | \_ | _/| %e A334144 | | | | | \_|_/ | %e A334144 4 4 3 4 4 => 4 3 %e A334144 | | | | | | _/ %e A334144 | | | | | |_/ %e A334144 2 2 2 2 2 => 2 %e A334144 | | | | | | %e A334144 | | | | | | %e A334144 1 1 1 1 1 => 1 %e A334144 Because the maximum number of distinct terms in any row is 3, a(15) = 3. %t A334144 Max[Length@ Union@ # & /@ Transpose@ #] & /@ Nest[Function[{a, n}, Append[a, Join @@ Table[Flatten@ Prepend[#, n] & /@ a[[n - n/p]], {p, FactorInteger[n][[All, 1]]}]]] @@ {#, Length@ # + 1} &, {{{1}}}, 105] %t A334144 (* Second program: *) %t A334144 g[n_] := Block[{lst = {{n}}}, While[lst[[-1]] != {1}, lst = Join[lst, {Union@ Flatten[# - #/(First@ # & /@ FactorInteger@ #) & /@ lst[[-1]] ]}]]; Max[Length /@ lst]]; Array[g, 105] (* _Robert G. Wilson v_, May 08 2020 *) %Y A334144 Cf. A064097, A332992, A332999, A333123, A334111, A334184. %Y A334144 Cf. also A096825. %K A334144 nonn %O A334144 1,6 %A A334144 _Michael De Vlieger_, _Peter Kagey_, _Antti Karttunen_, Apr 15 2020