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 A097257 #27 May 28 2016 15:06:38 %S A097257 0,10,110,120,1210,1220,1320,1330,13310,13320,13420,13430,14520,14530, %T A097257 14630,14640,146410,146420,146520,146530,147620,147630,147730,147740, %U A097257 159720,159730,159830,159840,160930,160940,161040,161050,1610510 %N A097257 Numbers whose set of base 11 digits is {0,A}, where A base 11 = 10 base 10. %C A097257 n such that there exists a permutation p_1, ..., p_n of 1, ..., n such that i + p_i is a power of 11 for every i. %H A097257 Vincenzo Librandi, <a href="/A097257/b097257.txt">Table of n, a(n) for n = 0..1000</a> %F A097257 a(n) = 10*A033047(n). %F A097257 a(2n) = 11*a(n), a(2n+1) = a(2n)+10. %t A097257 f[n_] := FromDigits[ IntegerDigits[n, 2] /. {1 -> 10}, 11]; Array[f, 33, 0] (* or much slower *) %t A097257 fQ[n_] := Union@ Join[{0, 10}, IntegerDigits[n, 11]] == {0, 10}; Select[ Range[0, 1610519], fQ] (* _Robert G. Wilson v_, May 12 2012 *) %t A097257 Join[{0},Union[Flatten[Table[FromDigits[#,11]&/@(Join[{10},#]&/@ Tuples[ {10,0},n]),{n,0,5}]]]] (* _Harvey P. Dale_, Sep 23 2013 *) %o A097257 (PARI) {for(vv=0,32, %o A097257 bvv=binary(vv); %o A097257 texp=0;btb=0; %o A097257 forstep(i=length(bvv),1,-1,btb=btb+10*bvv[i]*11^texp;texp++); %o A097257 print1(btb,", ") )} \\ _Douglas Latimer_, May 12 2012 %Y A097257 Cf. A001196, A005823, A097251-A097262. %K A097257 nonn,base %O A097257 0,2 %A A097257 _Ray Chandler_, Aug 03 2004