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%I #12 Sep 13 2018 02:42:11
%S 0,1,0,3,0,1,0,4,0,1,0,3,0,1,0,7,0,1,0,3,0,1,0,4,0,1,0,3,0,1,0,8,0,1,
%T 0,3,0,1,0,4,0,1,0,3,0,1,0,7,0,1,0,3,0,1,0,4,0,1,0,3,0,1,0,10,0,1,0,3,
%U 0,1,0,4,0,1,0,3,0,1,0,7,0,1,0,3,0,1,0,4,0,1,0,3,0,1,0,8,0,1,0,3,0,1,0,4,0
%N The 2-adic valuation of A318454(n).
%H Antti Karttunen, <a href="/A318455/b318455.txt">Table of n, a(n) for n = 1..65537</a>
%F a(n) = A007814(A318454(n)).
%t f[1] = 1; f[n_] := f[n] = 1/2 (Sum[Mod[d, 2], {d, Divisors[n]}] - Sum[f[d] f[n/d], {d, Divisors[n][[2 ;; -2]]}]);
%t a[n_] := IntegerExponent[Denominator[f[n]], 2];
%t Array[a, 105] (* _Jean-François Alcover_, Sep 13 2018 *)
%o (PARI) A318455(n) = valuation(A318454(n),2); \\ Needs also program from A318454.
%Y Cf. A001227, A007814, A318453, A318454.
%Y Cf. also A046645, A317946, A318315, A318451.
%K nonn
%O 1,4
%A _Antti Karttunen_ and _Andrew Howroyd_, Aug 29 2018