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A321473 Nonnegative numbers whose nonzero digits in ternary expansion are palindromic. 2

%I

%S 0,1,2,3,4,6,8,9,10,12,13,16,18,20,23,24,26,27,28,30,31,34,36,37,39,

%T 40,46,48,52,54,56,59,60,62,65,68,69,72,74,78,80,81,82,84,85,88,90,91,

%U 93,94,100,102,106,108,109,111,112,117,118,120,121,130,136,138

%N Nonnegative numbers whose nonzero digits in ternary expansion are palindromic.

%C This sequence corresponds to the fixed points of A321464, and contains A014190.

%H Harvey P. Dale, <a href="/A321473/b321473.txt">Table of n, a(n) for n = 1..1000</a>

%e For n = 1594426:

%e - the ternary expansion of 1594426 is "10000000010211",

%e - the corresponding nonzero digits are "11211", which are palindromic,

%e - hence 1594426 belongs to the sequence.

%t Select[Range[0,200],PalindromeQ[FromDigits[IntegerDigits[#,3]/.(0-> Nothing)]]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jun 22 2020 *)

%o (PARI) is(n, base=3) = my (t=select(sign, digits(n, base))); t==Vecrev(t)

%Y Cf. A014190, A321464.

%K nonn,base

%O 1,3

%A _Rémy Sigrist_, Nov 11 2018

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Last modified June 24 14:24 EDT 2021. Contains 345417 sequences. (Running on oeis4.)