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 A222729 #6 Oct 09 2021 17:28:40 %S A222729 9,99,909,939,949,959,969,979,989,999,9009,9119,9229,9339,9449,9559, %T A222729 9669,9779,9889,9999,90009,90109,90209,90309,90409,90509,90609,90809, %U A222729 90909,91119,91219,91319,91419,91519,91619,91719,91819,91919,92029,92129,92229,92329 %N A222729 Palindromic composite numbers starting with a digit 9. %C A222729 Subsequence of A032350 (palindromic nonprime numbers) and A002113 (palindromic numbers). Complement of A128375 (palindromic primes starting with a digit 9) with respect to A043044 (palindromic numbers starting with a digit 9). %H A222729 Jaroslav Krizek, <a href="/A222729/b222729.txt">Table of n, a(n) for n = 1..1050</a> %t A222729 Select[Range[100000],PalindromeQ[#]&&CompositeQ[#]&&IntegerDigits[#][[1]] == 9&] (* _Harvey P. Dale_, Oct 09 2021 *) %Y A222729 Cf. A032350, A002113, A128375, A043044. %K A222729 nonn,base %O A222729 1,1 %A A222729 _Jaroslav Krizek_, Mar 03 2013