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 A270359 #11 Mar 16 2016 00:38:14
%S A270359 1,2,4,17,36,369,1820,20808,47280,246561,6919153,16008300,1086517900,
%T A270359 5924129729,13855173264,982740019940,30127233316440,167427203210673,
%U A270359 5203545562472737,12300752138736600,913640750713307860,162500024938034177361
%N A270359 Positive integer averages of first n Pell numbers; Sum{k=0..n-1} A000129(k) / n where n is in A270342.
%e A270359 17 is a term because (0 + 1 + 2 + 5 + 12 + 29 + 70) / 7 = 119 / 7 = 17.
%o A270359 (PARI) a048739(n) = local(w=quadgen(8)); -1/2+(3/4+1/2*w)*(1+w)^n+(3/4-1/2*w)*(1-w)^n;
%o A270359 for(n=1, 1e2, if(a048739(n-1) % (n+1) == 0, print1(a048739(n-1) / (n+1) , ", ")));
%Y A270359 Cf. A000129, A048739, A270342.
%K A270359 nonn
%O A270359 1,2
%A A270359 _Altug Alkan_, Mar 15 2016