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%I #18 Dec 21 2016 14:54:13
%S 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 138,76,156,88,184,96,214,112,234,128,258,140,294,158,318,174,358,186,
%U 400,206,424,228,470,244,512,264,544,288,596,306,636,330,672,358,730
%N a(n) = 1 + Sum_{i=0..floor(n/2)} phi(n-2*i).
%C Number of Sturmian palindromes of length n.
%H 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 a(n) = A106481(n) + 1. - _Filip Zaludek_, Dec 16 2016
%p with(numtheory);
%p f:=n->1+add(phi(n-2*i),i=0..floor(n/2));
%p [seq(f(n),n=0..100)];
%t Table[1 + Sum[EulerPhi[n - 2 i], {i, 0, Floor[n/2]}], {n, 0, 59}] (* _Michael De Vlieger_, Dec 17 2016 *)
%Y Cf. A000010.
%K nonn
%O 0,2
%A _N. J. A. Sloane_, May 08 2013
%E Name corrected by _Michael De Vlieger_, Dec 17 2016
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