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%I #12 Sep 14 2024 06:50:09
%S 0,0,3,2,6,4,7,6,11,8,11,10,14,12,15,14,20,16,19,18,22,20,23,22,27,24,
%T 27,26,30,28,31,30,37,32,35,34,38,36,39,38,43,40,43,42,46,44,47,46,52,
%U 48,51,50,54,52,55,54,59,56,59,58,62,60,63,62,70,64,67,66,70
%N Exponent of 2 in (3^n-3)*2^(n-1).
%F Recurrence: a(2n) = a(n) + [(n+1)/2] + 1, a(2n+1) = 2n.
%F G.f.: Sum_{k>=0} t^2(3+2t+2t^3-t^4)/[(1+t^2)(1-t^2)^2], t=x^2^k.
%F a(n) = A093051(n) - 1 = A090740(n) + n - 2, for n >= 1. - _Amiram Eldar_, Sep 14 2024
%o (PARI) a(n)=if(n<1,0,if(n%2==0,a(n/2)+2*floor((n+2)/4)+1,n-1))
%Y Cf. A090740, A093051, A093052.
%Y a(n) is the exponent of 2 in A016129(n-1), A024281(n), A024287(n), A066406(n)/2, A071952(n+3).
%K nonn,changed
%O 0,3
%A _Ralf Stephan_, Mar 16 2004
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