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%I #11 Jul 19 2019 12:26:28
%S 1,16,52,160,9232,9232,4372,13120,39364,118096,1276936,1276936,
%T 6810136,9565936,28697812,86093440,1570824736,1570824736,2324522932,
%U 6973568800,20920706404,62762119216,188286357652,564859072960,9161049517720
%N Maximal term in Collatz-iteration started at -1+2^n.
%F a(n) = A025586(2^n-1).
%t Table[Max[NestWhileList[If[EvenQ[#],#/2,3#+1]&,2^n-1,#>1&]],{n,30}] (* _Harvey P. Dale_, Jul 19 2019 *)
%Y Cf. A025586.
%K nonn
%O 1,2
%A _Labos Elemer_, Sep 24 2003