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 A050783 #13 Aug 19 2021 06:41:01 %S A050783 0,1,2,3,4,5,6,7,8,9,101,121,131,141,151,161,171,181,191,202,212,232, %T A050783 242,252,262,272,282,292,303,313,323,343,353,363,373,383,393,404,414, %U A050783 424,434,454,464,474,484,494,505,515,525,535,545,565,575,585,595,606 %N A050783 Palindromes containing no pair of consecutive equal digits. %t A050783 Select[Range[0,610],Reverse[x=IntegerDigits[#]]==x&&FreeQ[Differences[x],0]&] (* _Jayanta Basu_, Jun 01 2013 *) %Y A050783 Cf. A002113, A050784, A030147, A046075. %K A050783 nonn,base %O A050783 1,3 %A A050783 _Patrick De Geest_, Sep 15 1999