A249309 - OEIS

%I #7 Oct 25 2014 05:08:41

%S 1,2,3,5,7,13,20,35,54,96,150,264,414,726,1140,1997,3136,5495,8631,

%T 15121,23752,41612,65363,114513,179876,315132,495008,867223,1362230,

%U 2386544,3748774,6567622,10316396

%N First row of spectral array W(Pi/2).

%H A. Fraenkel and C. Kimberling, <a href="http://dx.doi.org/10.1016/0012-365X(94)90259-3">Generalized Wythoff arrays, shuffles and interspersions</a>, Discrete Mathematics 126 (1994) 137-149.

%o (PARI)

%o \\ The first row of the generalized Wythoff array W(h),

%o \\   where h is an irrational number between 1 and 2.

%o row1(h, m) = {

%o   my(

%o     a=vector(m, n, floor(n*h)),

%o     b=setminus(vector(m, n, n), a),

%o     w=[a[1]^2, b[a[1]]],

%o     j=3

%o   );

%o   while(1,

%o     if(j%2==1,

%o       if(w[j-1]<=#a, w=concat(w, a[w[j-1]]), return(w))

%o     ,

%o       if(w[j-2]<=#b, w=concat(w, b[w[j-2]]), return(w))

%o     );

%o     j++

%o   );

%o   w

%o }

%o allocatemem(10^9)

%o row1(Pi/2, 10^7)

%Y Cf. A007068, A022159, A022161, A022163, A022165.

%K nonn

%O 1,2

%A _Colin Barker_, Oct 25 2014