A004505 - OEIS

%I #7 Oct 26 2023 22:57:09

%S 16,17,15,10,11,9,13,14,12,25,26,24,19,20,18,22,23,21,7,8,6,1,2,0,4,5,

%T 3,43,44,42,37,38,36,40,41,39,52,53,51,46,47,45,49,50,48,34,35,33,28,

%U 29,27,31,32,30,70,71,69,64

%N Tersum n + 16.

%F Tersum m + n: write m and n in base 3 and add mod 3 with no carries; e.g., 5 + 8 = "21" + "22" = "10" = 1.

%K nonn

%O 0,1

%A _N. J. A. Sloane_