%I
%S 0,0,0,1,2,0,2,0,1,3,4,5,7,8,6,2,0,1,6,7,8,1,2,0,5,3,4,9,10,11,13,14,
%T 12,17,15,16,21,22,23,25,26,24,20,18,19,6,7,8,1,2,0,5,3,4,18,19,20,22,
%U 23,21,26,24,25,3,4,5,7,8,6,2,0,1,15,16,17,10,11,9,14,12,13,27,28,29
%N Derivative of n in base 3.
%H Reinhard Zumkeller, <a href="/A038555/b038555.txt">Table of n, a(n) for n = 0..10000</a>
%F Write n in ternary, replace each pair of adjacent digits by their modulo 3 sum.
%e 15 = 120 in ternary, derivative is 02 = 2, so a(15)=2.
%o (Haskell)
%o a038555 n = foldr (\d v > v * 3 + d) 0 $
%o zipWith (\x y > (x + y) `mod` 3) ts $ tail ts
%o where ts = a030341_row n
%o  _Reinhard Zumkeller_, May 26 2013
%o (J) ab3 =: 3&#.^:_1
%o sp =: 2&(+/\)"1
%o > (3  sp)&.ab3&.> ;/ i. 100 NB. _Stephen Makdisi_, May 26 2018
%Y Cf. A038554.
%Y Cf. A030341.
%K nonn,nice,easy,base
%O 0,5
%A _N. J. A. Sloane_
%E More terms from _Erich Friedman_
%E Formula corrected by _Reinhard Zumkeller_, May 26 2013
