%I A004497
%S A004497 8,6,7,2,0,1,5,3,4,17,15,16,11,9,10,14,12,13,26,24,25,20,
%T A004497 18,19,23,21,22,35,33,34,29,27,28,32,30,31,44,42,43,38,
%U A004497 36,37,41,39,40,53,51,52,47,45,46,50,48,49,62,60,61,56
%N A004497 Tersum n + 8.
%F A004497 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.
%F A004497 a(n)= -5 + Sum_{k=0..n}{(1/36)*(-47*(k mod 9)-11*((k+1) mod 9)+25*((k+2) 
               mod 9)-11*((k+3) mod 9)-11*((k+4) mod 9)-11*((k+5) mod 9)+25*((k+6) 
               mod 9)-11*((k+7) mod 9)+61*((k+8) mod 9)},with n>=0 - Paolo P. Lava 
               (ppl(AT)spl.at), Dec 03 2007
%Y A004497 Sequence in context: A154499 A092750 A153791 this_sequence A091899 A104175 
               A019792
%Y A004497 Adjacent sequences: A004494 A004495 A004496 this_sequence A004498 A004499 
               A004500
%K A004497 nonn
%O A004497 0,1
%A A004497 N. J. A. Sloane (njas(AT)research.att.com).