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%I #11 Jul 25 2024 02:49:20
%S 0,1,2,2,4,2,3,4,4,5,6,2,4,6,4,6,8,2,3,4,4,5,6,6,7,8,4,5,6,6,7,8,8,9,
%T 10,2,4,6,4,6,8,6,8,10,4,6,8,6,8,10,8,10,12,2,3,4,4,5,6,6,7,8,4,5,6,6,
%U 7,8,8,9,10,6,7,8,8,9,10,10,11,12,4,5,6,6,7,8
%N Sum of digits of n-th base 3 palindrome.
%t Total/@Select[IntegerDigits[Range[0,2000],3],#==Reverse[#]&] (* _Harvey P. Dale_, Aug 08 2019 *)
%o (Python)
%o from gmpy2 import digits
%o def A043262(n):
%o if n == 1: return 0
%o y = 3*(x:=3**(len(digits(n>>1, 3))-1))
%o return int((s:=digits(n-x,3))[-1])+(sum(int(d) for d in s[:-1])<<1) if n<x+y else sum(map(int,digits(n-y,3)))<<1 # _Chai Wah Wu_, Jul 24 2024
%Y Cf. A014190 (base 3 palindromes)
%K nonn,base
%O 1,3
%A _Clark Kimberling_
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