A297568 Number of nonisomorphic proper colorings of partition star graph using four colors.
4, 12, 24, 36, 40, 108, 108, 60, 216, 180, 324, 324, 84, 360, 540, 648, 972, 972, 972, 112, 540, 1080, 660, 1080, 2916, 1512, 1944, 2916, 2916, 2916, 144, 756, 1800, 1980, 1620, 5832, 4860, 4536, 3240, 8748, 8748, 5832, 8748, 8748, 8748, 180, 1008, 2700, 3960, 1980, 2268, 9720, 14580, 9072, 13608, 4860, 17496, 14580, 26244, 13284, 9720, 26244, 26244, 17496, 26244, 26244, 26244, 220, 1296, 3780, 6600, 5940, 3024, 14580
Offset: 0
Examples
Rows are: 4; 12; 24, 36; 40, 108, 108; 60, 216, 180, 324, 324; 84, 360, 540, 648, 972, 972, 972;
Links
- Marko Riedel et al., Orbital chromatic polynomials
Programs
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Maple
b:= (n, i)-> `if`(n=0, [4], `if`(i<1, [], [seq(map(x-> x* binomial(3^i+j-1, j), b(n-i*j, i-1))[], j=0..n/i)])): T:= n-> b(n$2)[]: seq(T(n), n=0..10); # Alois P. Heinz, Jan 14 2018
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Mathematica
b[n_, i_] := If[n == 0, {4}, If[i<1, {}, Table[Map[Function[x, x*Binomial[ 3^i + j - 1, j]], b[n - i*j, i - 1]], {j, 0, n/i}]] // Flatten]; T[n_] := b[n, n]; Table[T[n], {n, 0, 10}] // Flatten (* Jean-François Alcover, Jan 17 2018, after Alois P. Heinz *)
Formula
For a partition lambda we have the OCP: k Product_{p^v in lambda} C((k-1)^p+v-1, v). Here we have k=4.
Comments