This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A043078 #10 Jun 21 2025 15:08:30 %S A043078 1,8,64,65,66,67,68,69,70,71,72,568,578,588,598,608,618,628,638,648, %T A043078 5104,5113,5122,5131,5140,5149,5158,5167,5176,5186,5195,5204,5213, %U A043078 5222,5231,5240,5249,5258,5268,5277,5286,5295,5304,5313 %N A043078 a(n)=(s(n)+2)/9, where s(n)=n-th base 9 palindrome that starts with 7. %H A043078 Harvey P. Dale, <a href="/A043078/b043078.txt">Table of n, a(n) for n = 1..1600</a> %t A043078 (#+2)/9&/@Select[Range[100000],IntegerDigits[#,9][[1]]==7&&PalindromeQ[IntegerDigits[#,9]]&] (* _Harvey P. Dale_, Jun 21 2025 *) %K A043078 nonn,base %O A043078 1,2 %A A043078 _Clark Kimberling_