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%I #13 Sep 07 2023 04:43:03
%S 1,2,3,4,0,7,8,5,6,15,16,0,0,0,31,32,9,11,12,14,63,64,0,10,0,13,0,127,
%T 128,17,0,23,24,0,30,255,256,0,19,0,0,0,28,0,511,512,33,18,20,47,48,
%U 27,29,62,1023,1024,0,0,0,22,0,25,0,0,0,2047,2048,65,35,39,21,95,96,26,56
%N A054424 expanded to normal triangular array, with zeros at those (x,y) where x and y are not relatively prime.
%p position_in_whole_SB_tree_or_zero := (n,m) -> `if`((1 = gcd(n,m)),(frac2position_in_whole_SB_tree(n/m)),(0));
%p A054424_as_array := n -> position_in_whole_SB_tree_or_zero( ((n-((trinv(n)*(trinv(n)-1))/2))+1), ((((trinv(n)-1)*(((1/2)*trinv(n))+1))-n)+1) );
%p trinv := n -> floor((1+sqrt(1+8*n))/2); # Gives integral inverses to the triangular numbers
%Y Cf. A054424, A054431.
%K nonn,tabl,nice
%O 1,2
%A _Antti Karttunen_