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A025512 Index of n-th 2 in A022300.

%I A025512 #9 Nov 03 2016 01:38:11
%S A025512 3,5,8,11,13,14,16,19,22,23,25,26,28,31,33,34,37,40,41,43,44,46,49,52,
%T A025512 53,55,58,60,61,64,67,68,70,71,73,76,78,79,82,85,87,88,90,91,94,96,97,
%U A025512 99,102,103,105,106,109,112,114,115,117,118,121,123,124,126,129,132,133,135
%N A025512 Index of n-th 2 in A022300.
%H A025512 Robert Israel, <a href="/A025512/b025512.txt">Table of n, a(n) for n = 1..10000</a>
%p A025512 N:= 10^3: # to get all terms <= N
%p A025512 B:= Vector(N):
%p A025512 B[1..4]:= <1,1,2,1>:
%p A025512 m:= 4: t:= 2:
%p A025512 for n from 1 while m < N do
%p A025512   t:= 3-t;
%p A025512   B[m]:= t;
%p A025512   if B[n] = 2 and m+1 < N then
%p A025512      B[m+1]:= t; m:= m+2
%p A025512   else m:= m+1
%p A025512   fi
%p A025512 od:
%p A025512 select(t -> B[t]=2, [$1..N]); # _Robert Israel_, Nov 02 2016
%K A025512 nonn
%O A025512 1,1
%A A025512 _David W. Wilson_