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 A072427 #8 Aug 11 2014 22:45:22 %S A072427 0,2,4,6,8,10,11,12,14,16,18,101,141,161,181,198,201,221,241,261,281, %T A072427 1001,1818,1838,1858,1878,1898,1918,1938,1958,1978,1998,2981,10001, %U A072427 10201,10401,10601,10801,11001,11201,11401,11601,11801,18018,19998 %N A072427 Numbers n for which there is a unique k such that n = k + reverse(k). %C A072427 Subsequence of A067030. First term is A072041(1). A068065 is a subsequence of this sequence. %H A072427 T. D. Noe, <a href="/A072427/b072427.txt">Table of n, a(n) for n = 1..123</a> %H A072427 <a href="/index/Res#RAA">Index entries for sequences related to Reverse and Add!</a> %e A072427 18 = 9 + 9; 261 = 180 + 081; 11401 = 10700 + 00701. %t A072427 revAdd[n_] := n + FromDigits[Reverse[IntegerDigits[n]]]; ra=Table[revAdd[n], {n, 0, 10^5}]; t=Sort[Tally[ra]]; First /@ Select[t, #[[2]] == 1 && #[[1]] <= Length[ra] &] %o A072427 (ARIBAS) var n,k,c,i,rev: integer; st,nst: string; end; m := 1; for n := 0 to 29000 do k := n div 2; c := 0; while k <= n and c < m + 1 do st := itoa(k); nst := ""; for i := 0 to length(st) - 1 do nst := concat(st[i],nst); end; rev := atoi(nst); if n = k + rev then inc(c); if k mod 10 <> 0 and k <> rev then inc(c); end; end; inc(k); end; if c = m then write(n,","); end; end; %Y A072427 Cf. A067030, A068065, A072041, A072040, A071914. %K A072427 base,nonn %O A072427 1,2 %A A072427 _Klaus Brockhaus_, Jun 17 2002