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 A133377 #37 Mar 20 2025 04:35:12 %S A133377 0,1,2,3,4,5,6,7,8,9,53,371,5141,99481 %N A133377 Complete list of decimal numbers that when converted to hexadecimal produce the mirror image of the original number. %C A133377 There are 14 numbers in all, including single-digit numbers. %e A133377 53 = 35_16; 371 = 173_16. %t A133377 Select[Range[0,10^5],IntegerDigits[#]==Reverse[IntegerDigits[#,16]]&] (* _James C. McMahon_, Mar 17 2025 *) %o A133377 (PARI) isok(n) = digits(n, 10) == Vecrev(digits(n, 16)); \\ _Michel Marcus_, Oct 05 2019 %Y A133377 Subsequence of A133287. For n > 1, subsequence of A034294. %K A133377 base,easy,fini,nonn,full %O A133377 1,3 %A A133377 _Daniel Mondot_, Dec 21 2007