A366108 a(n) = floor(binomial(n-1, floor((n-1)/2))/2).
1, 1, 3, 5, 10, 17, 35, 63, 126, 231, 462, 858, 1716, 3217, 6435, 12155, 24310, 46189, 92378, 176358, 352716, 676039, 1352078, 2600150, 5200300, 10029150, 20058300, 38779380, 77558760, 150270097, 300540195, 583401555, 1166803110, 2268783825, 4537567650, 8836315950
Offset: 3
Keywords
Links
- Gábor Czédli, Minimum-sized generating sets of the direct powers of the free distributive lattice on three generators and a Sperner theorem, arXiv:2309.13783 [math.CO], 2023. See formulas (3.6) at p. 4 and (4.15) at p. 8.
Programs
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Mathematica
a[n_]:=Floor[Binomial[n-1,Floor[(n-1)/2]]/2]; Array[a,36,3]
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PARI
a(n) = binomial(n-1, (n-1)\2)\2; \\ Michel Marcus, Sep 30 2023