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 A225373 #18 Dec 21 2016 14:54:13
%S A225373 1,2,2,4,4,8,6,14,10,20,14,30,18,42,24,50,32,66,38,84,46,96,56,118,64,
%T A225373 138,76,156,88,184,96,214,112,234,128,258,140,294,158,318,174,358,186,
%U A225373 400,206,424,228,470,244,512,264,544,288,596,306,636,330,672,358,730
%N A225373 a(n) = 1 + Sum_{i=0..floor(n/2)} phi(n-2*i).
%C A225373 Number of Sturmian palindromes of length n.
%H A225373 Michelangelo Bucci, Alessandro De Luca, Amy Glen and Luca Q. Zamboni, <a href="http://arxiv.org/abs/0802.1332">A connection between palindromic and factor complexity using return words</a>, arXiv:0802.1332 [math.CO], 2008.
%F A225373 a(n) = A106481(n) + 1. - _Filip Zaludek_, Dec 16 2016
%p A225373 with(numtheory);
%p A225373 f:=n->1+add(phi(n-2*i),i=0..floor(n/2));
%p A225373 [seq(f(n),n=0..100)];
%t A225373 Table[1 + Sum[EulerPhi[n - 2 i], {i, 0, Floor[n/2]}], {n, 0, 59}] (* _Michael De Vlieger_, Dec 17 2016 *)
%Y A225373 Cf. A000010.
%K A225373 nonn
%O A225373 0,2
%A A225373 _N. J. A. Sloane_, May 08 2013
%E A225373 Name corrected by _Michael De Vlieger_, Dec 17 2016