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%I #5 Mar 30 2012 18:37:10
%S 2,5,8,11,13,17,19,22,25,28,30,33,37,39,43,45,48,50,53,57,59,63,65,67,
%T 71,74,76,79,82,85,87,91,94,97,100,102,105,108,111,113,115,119,122,
%U 126,128,130,133,135,139,142,145,148,150,154,156,160,163,165,168,171,173
%N Let sequences X and Y consist of the least positive integers such that 2X+Y is the complement of X and X+Y is the complement of Y, starting with X(1)=1 and Y(1)=1; then this sequence equals X+Y, while X=A141204, 2X+Y=A141205, Y=A141206.
%C Complement of A141207.
%H Paul D Hanna, <a href="/A141207/b141207.txt">Table of n, a(n) for n = 1..420</a>
%F CONJECTURES on evaluating limits.
%F The following limits exist for some irrational q and r:
%F Limit X(n)/n = 1 + q, Limit {2X+Y}(n)/n = 1 + 1/q and
%F Limit Y(n)/n = 1 + r, Limit {X+Y}(n)/n = 1 + 1/r.
%F Thus q and r can be defined by:
%F Limit X(n)/{2X+Y}(n) = q = (1 + q)/(3 + 2*q + r) and
%F Limit Y(n)/{X+Y}(n) = r = (1 + r)/(2 + r + q).
%F Therefore q = least positive real root that satisfies:
%F 1 - 4*q + 2*q^2 + 2*q^3 = 0, giving q = 0.31544880690757230308868993...
%F Also, r = least positive real root that satisfies:
%F 2 - 4*r + r^3 = 0, giving r = 0.5391888728108891165258759...
%e Union of X and 2X+Y = positive integers:
%e X=[1,2,4,5,6,8,9,10,11,13,14,15,17,18,20,21,22,23,24,...];
%e 2X+Y=[3,7,12,16,19,25,28,32,36,41,44,48,54,57,63,66,70,...].
%e Limit X(n)/{2X+Y}(n) = 0.3154488069...
%e Union of Y and X+Y = positive integers:
%e Y=[1,3,4,6,7,9,10,12,14,15,16,18,20,21,23,24,26,27,29,...];
%e X+Y=[2,5,8,11,13,17,19,22,25,28,30,33,37,39,43,45,48,50,...].
%e Limit Y(n)/{X+Y}(n) = 0.5391888728...
%o (PARI) /* Print a(n), n=1..100: */ {A=[1]; B=[3]; C=[1]; D=[2]; print1(D[1]","); for(n=1, 100, for(j=2, 4*n, if(setsearch(Set(concat(A, B)), j)==0, At=concat(A, j); for(k=2*j+1, 6*n, if(setsearch(Set(concat(At, B)), k)==0, if(setsearch(Set(concat(C, D)), k-2*j)==0, if(setsearch(Set(concat(C, D)), k-j)==0, A=At; B=concat(B, k); C=concat(C, k-2*j); D=concat(D, k-j); print1(D[ #D]","); break); break))))))}
%Y Cf. A141204 (X), A141205 (2X+Y), A141206 (Y).
%K nonn
%O 1,1
%A _Paul D. Hanna_, Jun 21 2008
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