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%I #8 Nov 28 2019 08:07:10
%S 1,1,2,3,7,13,23,45,86,159,303,568,1069,2005,3769,7066,13251,24821,
%T 46482,86988,162758
%N Number of compositions of n with cuts-resistance <= 2.
%C A composition of n is a finite sequence of positive integers summing to n.
%C For the operation of shortening all runs by 1, cuts-resistance is defined to be the number of applications required to reach an empty word.
%e The a(0) = 1 through a(5) = 13 compositions:
%e () (1) (2) (3) (4) (5)
%e (1,1) (1,2) (1,3) (1,4)
%e (2,1) (2,2) (2,3)
%e (3,1) (3,2)
%e (1,1,2) (4,1)
%e (1,2,1) (1,1,3)
%e (2,1,1) (1,2,2)
%e (1,3,1)
%e (2,1,2)
%e (2,2,1)
%e (3,1,1)
%e (1,1,2,1)
%e (1,2,1,1)
%t degdep[q_]:=Length[NestWhileList[Join@@Rest/@Split[#]&,q,Length[#]>0&]]-1;
%t Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],degdep[#]<=2&]],{n,0,10}]
%Y Sum of first three columns of A329861.
%Y Compositions with cuts-resistance 1 are A003242.
%Y Compositions with cuts-resistance 2 are A329863.
%Y Compositions with runs-resistance 2 are A329745.
%Y Numbers whose binary expansion has cuts-resistance 2 are A329862.
%Y Binary words with cuts-resistance 2 are A027383.
%Y Cuts-resistance of binary expansion is A319416.
%Y Binary words counted by cuts-resistance are A319421 or A329860.
%Y Cf. A000975, A003242, A032020, A114901, A240085, A261983, A319420, A329738, A329744, A329864.
%K nonn,more
%O 0,3
%A _Gus Wiseman_, Nov 27 2019