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Search: id:A131502
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| A131502 |
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Half the number of permutations of 0..n with a zero n-th difference. |
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+0
1
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| 0, 0, 1, 1, 8, 3, 136, 29, 928, 942, 66496, 6175, 2785856, 205678, 11122048
(list; graph; listen)
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OFFSET
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0,5
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EXAMPLE
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a(5)=3 because 0,1,2,3,4,5 ; 0,2,4,3,1,5 ; and 0,4,2,1,3,5 ; and their reverses have zero 5th differences.
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CROSSREFS
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Sequence in context: A004734 A049074 A038281 this_sequence A100253 A088397 A021123
Adjacent sequences: A131499 A131500 A131501 this_sequence A131503 A131504 A131505
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KEYWORD
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nonn
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AUTHOR
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Ron Hardin (rhhardin(AT)att.net), Aug 13 2007
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