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%I #6 Dec 21 2017 04:38:10
%S 0,0,1,2,1,2,2,2,3,1,2,2,2,2,2,2,2,3,3,2,2,3,2,2,2,2,3,2,3,2,2,3,3,2,
%T 2,3,3,2,2,3,2,3,3,3,3,2,3,3,2,3,3,3,3,3,3,2,3,3,3,3,3,3,3,2,3,2,2,3,
%U 2,3,3,3,3,2,2,3,2,2,2,2,3,2,2,3,2,3,3,2
%N Additive persistence of Cullen numbers.
%e Cullen number 385 --> 3+8+5=16 -->1+6=7 thus persistence is 2
%p with(numtheory): with(combinat): P:=proc(n) local a,t;t:=0; a:=n*2^n+1; while a>9 do t:=t+1; a:=convert(convert(a,base,10),`+`); od; t;
%p end: seq(P(i),i=1..10^2);
%Y Cf. A002064, A131837.
%K easy,nonn,base
%O 1,4
%A _Paolo P. Lava_ and _Giorgio Balzarotti_, Jul 20 2007
%E Corrected entries and Maple code by _Paolo P. Lava_, Dec 19 2017