A043056 - OEIS

%I #9 Feb 13 2023 19:57:18

%S 1,4,19,20,21,22,23,24,109,116,123,130,137,144,649,655,661,667,673,

%T 679,686,692,698,704,710,716,723,729,735,741,747,753,760,766,772,778,

%U 784,790,797,803,809,815,821,827,834,840,846,852

%N a(n)=(s(n)+3)/6, where s(n)=n-th base 6 palindrome that starts with 3.

%H Harvey P. Dale, <a href="/A043056/b043056.txt">Table of n, a(n) for n = 1..500</a>

%t b6p3Q[n_]:=Module[{idn6=IntegerDigits[n,6]},idn6==Reverse[idn6]&&idn6[[1]] == 3]; (#+3)/6&/@Select[Range[10000],b6p3Q] (* _Harvey P. Dale_, Feb 13 2023 *)

%K nonn,base

%O 1,2

%A _Clark Kimberling_