A055947 - OEIS

%I #15 May 14 2022 17:12:22

%S 0,0,0,2,0,-2,4,2,0,8,0,-8,8,0,-8,8,0,-8,16,8,0,16,8,0,16,8,0,26,0,

%T -26,20,-6,-32,14,-12,-38,32,6,-20,26,0,-26,20,-6,-32,38,12,-14,32,6,

%U -20,26,0,-26,52,26,0,46,20,-6,40,14,-12,58,32,6,52,26,0,46,20,-6,64,38,12,58,32,6,52,26,0,80,0,-80,56,-24,-104,32,-48

%N n - reversal of base 3 digits of n (written in base 10).

%C a(n) is even.

%H Indranil Ghosh, <a href="/A055947/b055947.txt">Table of n, a(n) for n = 0..20000</a>

%F a(n) = n - A030102(n).

%e For n = 5, the reversal of base 3 digits of n (written in base 10) is 7. So, a(5) = 5 - 7 = -2. - _Indranil Ghosh_, Feb 01 2017

%t Table[n-FromDigits[Reverse[IntegerDigits[n,3]],3],{n,0,90}] (* _Harvey P. Dale_, May 14 2022 *)

%o (PARI) a(n) = n - fromdigits(Vecrev(digits(n, 3)), 3); \\ _Michel Marcus_, Aug 09 2019

%Y Cf. A030102, A056965.

%K base,sign

%O 0,4

%A _Henry Bottomley_, Jul 18 2000