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A183565
Number of partitions of n containing a clique of size 8.
12
1, 0, 1, 1, 2, 2, 4, 4, 8, 9, 13, 16, 24, 28, 40, 49, 66, 82, 110, 132, 175, 214, 274, 336, 428, 520, 655, 798, 990, 1203, 1486, 1793, 2200, 2653, 3227, 3880, 4701, 5622, 6779, 8092, 9701, 11546, 13793, 16355, 19466, 23029, 27290, 32199, 38048, 44752, 52719
OFFSET
8,5
COMMENTS
All parts of a number partition with the same value form a clique. The size of a clique is the number of elements in the clique.
LINKS
FORMULA
G.f.: (1-Product_{j>0} (1-x^(8*j)+x^(9*j))) / (Product_{j>0} (1-x^j)).
EXAMPLE
a(12) = 2, because 2 partitions of 12 contain (at least) one clique of size 8: [1,1,1,1,1,1,1,1,2,2], [1,1,1,1,1,1,1,1,4].
MAPLE
b:= proc(n, i) option remember; `if`(n=0, [1, 0], `if`(i<1, [0, 0],
add((l->`if`(j=8, [l[1]$2], l))(b(n-i*j, i-1)), j=0..n/i)))
end:
a:= n-> (l-> l[2])(b(n, n)):
seq(a(n), n=8..60);
MATHEMATICA
max = 60; f = (1 - Product[1 - x^(8j) + x^(9j), {j, 1, max}])/Product[1 - x^j, {j, 1, max}]; s = Series[f, {x, 0, max}]; Drop[CoefficientList[s, x], 8] (* Jean-François Alcover, Oct 01 2014 *)
c8[n_]:=If[MemberQ[Tally[n][[All, 2]], 8], 1, 0]; Table[Total[c8/@ IntegerPartitions[ x]], {x, 8, 60}] (* Harvey P. Dale, Aug 12 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Jan 05 2011
STATUS
approved