Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #7 Jul 06 2020 19:56:22
%S 1,1,0,2,3,5,11,23,40,80,180,344,661,1321,2657,5268,10481,20903,41572,
%T 82734,164998,328304,654510,1305421,2598811,5182174,10332978,20594318,
%U 41066611,81897091,163309679,325707492,649648912,1295827380,2584941276,5156774487
%N Number of complete compositions of n whose run-lengths cover an initial interval of positive integers.
%C A composition of n is a finite sequence of positive integers with sum n. It is complete if it covers an initial interval of positive integers.
%e The a(0) = 1 through a(6) = 11 compositions (empty column not shown):
%e () (1) (1,2) (1,1,2) (1,2,2) (1,2,3)
%e (2,1) (1,2,1) (2,1,2) (1,3,2)
%e (2,1,1) (2,2,1) (2,1,3)
%e (1,1,2,1) (2,3,1)
%e (1,2,1,1) (3,1,2)
%e (3,2,1)
%e (1,2,1,2)
%e (1,2,2,1)
%e (2,1,1,2)
%e (2,1,2,1)
%e (1,1,2,1,1)
%t normQ[m_]:=Or[m=={},Union[m]==Range[Max[m]]];
%t Table[Length[Select[Join@@Permutations/@IntegerPartitions[n],normQ[#]&&normQ[Length/@Split[#]]&]],{n,0,10}]
%Y Looking at multiplicities instead of run-lengths gives A329748.
%Y The non-complete version is A329766.
%Y Complete compositions are A107429.
%Y Cf. A000740, A008965, A098504, A244164, A274174, A329738, A329739, A329740, A329741, A329744.
%K nonn
%O 0,4
%A _Gus Wiseman_, Nov 21 2019
%E a(21)-a(35) from _Alois P. Heinz_, Jul 06 2020