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%I #8 Mar 02 2015 16:08:46
%S 1,1,4,30,702,76844,50448952
%N 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.
%Y a(n)=A064049(n)/6 for n>1.
%K more,nonn
%O 1,3
%A _Floor van Lamoen_, Aug 24 2001
%E a(7) from _Lars Blomberg_, Apr 11 2012
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