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%I #4 Mar 30 2012 18:50:26
%S 1,1,1,3,3,2,1,2,1,1,2,2,1,1,2,1,2,1,3,1,2,1,1,1,2,1,1,2,1,1,1,1,1,1,
%T 1,2,1,1,1,1,4,1,1,2,1,1,1,1,2,1,1,1,1,1,1,1,1,2,2,1,1,1,2,1,1,1,2,1,
%U 1,1,1,2,2,2,1,1,1,1,1,2,1,1,1,2,3,1,1,1,1,1,3,1,2,1,2,1,1,1,1,1,1,1,1,1,4
%N Number of steps to reach the first nonprime (=A075523(n)) starting with the n-th prime p and iterating the map k -> 4*k+(p mod 4), or -1 if no integer is ever reached.
%C a(A075521(n)) > 1;
%C a(n) = a(A075520(n))+1 for n with A075520(n) prime.
%e A000040(4)=7 and (7 mod 4) = 3: 7 -> 4*7+3=31 -> 4*31+3=127 -> 4*127+3=511 = A075523(4), therefore a(4)=3.
%Y Cf. A075520, A075519.
%K nonn
%O 1,4
%A _Reinhard Zumkeller_, Sep 19 2002
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