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 A281378 #27 Jun 13 2025 18:16:48
%S A281378 0,1,2,5,6,66,77,626,5005,7777,22122,64446,87978,399993,1287821,
%T A281378 5614165,5679765,6407046,6865686,7107017,8349438,8547458,282777282,
%U A281378 1220330221,43474247434,43833533834,64630703646,68622322686,73855855837,1249451549421,2468208028642
%N A281378 Palindromic numbers which are also palindromic in their binary reflected Gray code representation.
%H A281378 Chai Wah Wu, <a href="/A281378/b281378.txt">Table of n, a(n) for n = 1..47</a>
%e A281378 626 is in the sequence because binary reflected Gray code for 626 is '1101001011' and both 626 and '1101001011' are palindromics.
%t A281378 Select[Range[10^7], And[Reverse@ # == # &@ IntegerDigits@ #, Reverse@ # == # &@ Abs[Prepend[Most@ #, 0] - #] &@ IntegerDigits[#, 2]] &] (* _Michael De Vlieger_, Jan 21 2017 *)
%o A281378 (Python)
%o A281378 def G(n):
%o A281378 return bin(n^(n//2))[2:]
%o A281378 i=1
%o A281378 j=1
%o A281378 while j<=23:
%o A281378 if i==int(str(i)[::-1]) and G(i)==G(i)[::-1]:
%o A281378 print(str(j)+" "+str(i))
%o A281378 j+=1
%o A281378 i+=1
%o A281378 (PARI) lista(nn) = {my(v, w); for(k=0, nn, if((w=digits(k))==Vecrev(w) && (v=binary(bitxor(k, k>>1)))==Vecrev(v), print1(k, ", "))); } \\ _Jinyuan Wang_, Mar 01 2020
%Y A281378 Cf. A002113, A006995, A014550, A281379.
%K A281378 nonn,base
%O A281378 1,3
%A A281378 _Indranil Ghosh_, Jan 20 2017
%E A281378 0 and more terms added by _Chai Wah Wu_, Jan 23 2017