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 A216237 #17 Mar 15 2013 16:51:36
%S A216237 1,7,44,262,313,383,404,464,565,656,818,888,989,1221,1771,1881,2112,
%T A216237 3553,4004,4554,4774,5335,5445,5555,7117,7447,7887,8118,8778,11311,
%U A216237 11811,12021,12321,12921,14641,15451,15951,17071,17371,18081,18381,20602,21012
%N A216237 Happy palindromic numbers.
%C A216237 That is, happy numbers (A007770) that are palindromic (A002113).
%H A216237 Reinhard Zumkeller, <a href="/A216237/b216237.txt">Table of n, a(n) for n = 1..1000</a>
%F A216237 A103369(a(n)) * A136522(a(n)) = 1. - _Reinhard Zumkeller_, Mar 15 2013
%t A216237 palQ[n_] := Block[{d=IntegerDigits@n}, d == Reverse@d]; happyQ[n_] := Block[{w = n}, While[w > 6, w = Total[IntegerDigits[w]^2]]; w == 1]; Select[Range[21012], palQ[#] && happyQ[#] &] (* _Giovanni Resta_, Mar 14 2013 *)
%o A216237 (Haskell)
%o A216237 a216237 n = a216237_list !! (n-1)
%o A216237 a216237_list = filter ((== 1) . a136522) a007770_list
%o A216237 -- _Reinhard Zumkeller_, Mar 15 2013
%Y A216237 Cf. A002113, A007770.
%K A216237 nonn,base,easy
%O A216237 1,2
%A A216237 _Jayanta Basu_, Mar 14 2013