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 A071242 #10 Jul 02 2025 16:02:01
%S A071242 0,1,2,3,4,5,6,7,8,9,11,22,33,44,55,11,22,33,44,55,22,33,44,55,66,22,
%T A071242 33,44,55,66,33,44,55,66,77,33,44,55,66,77,44,55,66,77,88,44,55,66,77,
%U A071242 88,55,66,77,88,99,101,202,303,404,505,111,212,313,414,515,121
%N A071242 Arithmetic mean of n and R(n) where n is a number such that the least significant digit and the most significant digits are of same parity and R(n) is its digit reversal (A004086).
%F A071242 {n + R(n)}/2 for all n which yield integers.
%p A071242 reversal := proc(n) local i, len, new, temp: new := 0: temp := n: len := floor(log[10](n+.1))+1: for i from 1 to len do new := new+irem(temp, 10)*10^(len-i): temp := floor(temp/10): od: RETURN(new): end: for n from 0 to 500 do if type((n+reversal(n))/2, integer) then printf(`%d,`,(n+reversal(n))/2) fi: od: # _James Sellers_, May 28 2002
%Y A071242 Cf. A071240, A071241.
%K A071242 base,nonn
%O A071242 0,3
%A A071242 _Amarnath Murthy_, May 20 2002
%E A071242 More terms from _James Sellers_, May 28 2002