A292549 Number of multisets of exactly n nonempty binary words with a total of 2n letters such that no word has a majority of 0's.
1, 3, 10, 33, 98, 291, 826, 2320, 6342, 17188, 45750, 120733, 314690, 813854, 2085363, 5306878, 13406382, 33665476, 84031608, 208655086, 515469203, 1267600993, 3103490884, 7567559622, 18381579206, 44487740012, 107301636460, 257967350824, 618279370985
Offset: 0
Keywords
Examples
a(0) = 1: {}. a(1) = 3: {01}, {10}, {11}. a(2) = 10: {1,011}, {1,101}, {1,110}, {1,111}, {01,01}, {01,10}, {01,11}, {10,10}, {10,11}, {11,11}.
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..3163
Crossrefs
Cf. A292506.
Programs
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Maple
g:= n-> 2^(n-1)+`if`(n::odd, 0, binomial(n, n/2)/2): a:= proc(n) option remember; `if`(n=0, 1, add(add(d* g(d+1), d=numtheory[divisors](j))*a(n-j), j=1..n)/n) end: seq(a(n), n=0..35);
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Mathematica
g[n_] := 2^(n-1) + If[OddQ[n], 0, Binomial[n, n/2]/2]; a[n_] := a[n] = If[n == 0, 1, Sum[Sum[d*g[d+1], {d, Divisors[j]}]*a[n-j], {j, 1, n}]/n]; Table[a[n], {n, 0, 35}] (* Jean-François Alcover, May 11 2019, after Alois P. Heinz *)
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