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Trajectory of 1 under morphism taking n to sorted divisors of n+1.
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%I #7 Jan 14 2023 08:46:07

%S 1,2,1,3,1,2,1,2,4,1,2,1,3,1,2,1,3,1,5,1,2,1,3,1,2,1,2,4,1,2,1,3,1,2,

%T 1,2,4,1,2,1,2,3,6,1,2,1,3,1,2,1,2,4,1,2,1,3,1,2,1,3,1,5,1,2,1,3,1,2,

%U 1,2,4,1,2,1,3,1,2,1,3,1,5,1,2,1,3,1,2,1,3,1,2,4,1,7,1,2,1,3,1,2,1,2,4,1,2

%N Trajectory of 1 under morphism taking n to sorted divisors of n+1.

%C 1 -> 1,2; 2->1,3; 3->1,2,4; ...

%H <a href="/index/Fi#FIXEDPOINTS">Index entries for sequences that are fixed points of mappings</a>

%F a(A117160(k+1)) = k (this is the first occurrence of k in the sequence). - _Rémy Sigrist_, Jan 14 2023

%e 1 -> 1,2 -> 1,2,1,3 -> 1,2,1,3,1,2,1,2,4 -> ...

%o (PARI) v=[1,2];for(i=2,60,v=concat(v,divisors(v[i]+1)));v

%Y Cf. A007001, A001511, A027750, A112682, A117160.

%K nonn

%O 1,2

%A _Franklin T. Adams-Watters_, Jul 10 2009