cp's OEIS Frontend

A064050 Number of essentially different (not mappable to each other by reflection or rotation) arrangements of numbers 1 to n*(n+1)/2 in a triangle of n rows, in such a way that each row and each diagonal is increasing or decreasing.

%I A064050 #14 Jul 20 2024 14:40:03
%S A064050 1,1,4,30,702,76844,50448952,230643876376,8267423666602776,
%T A064050 2588783179055230532664,7821803477915366921777312696,
%U A064050 249798463487076698389715808536913464,91691177557134991595405594421320691579192632,417955522215118460342460602239817237893422169776951160
%N A064050 Number of essentially different (not mappable to each other by reflection or rotation) arrangements of numbers 1 to n*(n+1)/2 in a triangle of n rows, in such a way that each row and each diagonal is increasing or decreasing.
%H A064050 Max Alekseyev, <a href="/A064050/b064050.txt">Table of n, a(n) for n = 1..18</a>
%Y A064050 a(n)=A064049(n)/6 for n>1.
%K A064050 nonn
%O A064050 1,3
%A A064050 _Floor van Lamoen_, Aug 24 2001
%E A064050 a(7) from _Lars Blomberg_, Apr 11 2012
%E A064050 Terms a(8) onward from _Max Alekseyev_, Jul 20 2024