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 A056962 #15 Oct 04 2018 12:13:40
%S A056962 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,1,17,33,49,65,81,97,113,129,
%T A056962 145,161,177,193,209,225,241,2,18,34,50,66,82,98,114,130,146,162,178,
%U A056962 194,210,226,242,3,19,35,51,67,83,99,115,131,147,163,179,195,211,227,243,4
%N A056962 Base 16 reversal of n (written in base 10).
%e A056962 a(17) = 17 because 17 in hexadecimal is 11, the same as its reverse.
%e A056962 a(18) = 33 because 18 in hexadecimal is 12, and hexadecimal 21 is 2 * 16 + 1 = 33.
%e A056962 a(19) = 49 because 19 in hexadecimal is 13, and hexadecimal 31 is 3 * 16 + 1 = 49.
%t A056962 Table[FromDigits[Reverse[IntegerDigits[n, 16]], 16], {n, 0, 127}] (* _Alonso del Arte_, Sep 30 2018 *)
%o A056962 (PARI) a(n) = fromdigits(Vecrev(digits(n, 16)), 16); \\ _Michel Marcus_, Sep 30 2018
%Y A056962 Cf. A004086, A030101-A030108, A056960-A056963, A029730.
%K A056962 base,nonn,easy
%O A056962 0,3
%A A056962 _Henry Bottomley_, Jul 18 2000