%I #6 Aug 24 2020 23:26:02
%S 2,3,5,7,13,17,19,31,49,61,83,89,107,127,167,179,197,233,241,269,281,
%T 347,373,421,443,457,487,521,607,697,769,829,881,1049,1063
%N Values k where A336719(k) increases.
%C Also, values k (record positions) where A005420(k) reaches a new maximum. For the maximum itself, see A336720.
%C A000043 is a subsequence.
%o (PARI) re=0;for(k=2,+oo,p=vecmax(factor(2^k-1)[,1]);if(p>re,re=p;print1(k,", ")))
%Y Cf. A000043, A005420, A336719, A336720.
%K nonn,hard,more
%O 1,1
%A _Jeppe Stig Nielsen_, Aug 01 2020