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A060426
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a(n) is the number of degrees in the sequence of the degrees of the irreducible representations of the symmetric group S_n that appear only once.
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2
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1, 0, 1, 1, 1, 1, 1, 2, 1, 2, 2, 3, 2, 3, 4, 4, 5, 5, 4, 6, 8, 8, 6, 7, 10, 11, 11, 15, 15, 16, 18, 21, 22, 23, 29, 33, 31, 31, 39, 43, 44, 52, 51, 58, 64, 71, 66, 82, 88, 96, 93, 103, 115, 128, 143, 150, 156, 160, 173, 199, 202, 202, 242, 263, 269, 293, 308
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OFFSET
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1,8
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COMMENTS
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LINKS
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EXAMPLE
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a(6) = 1 because the degrees for S_6 are 1,1,5,5,5,5,9,9,10,10,16 and the only number that appears once is 16.
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PROG
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(Sage)
mult = {}
for P in Partitions(n) :
dim = P.dimension()
mult[dim] = mult.get(dim, 0) + 1
return len([m for m in iter(mult) if mult[m]==1])
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Avi Peretz (njk(AT)netvision.net.il), Apr 05 2001
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EXTENSIONS
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STATUS
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approved
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