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A275063
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Number of permutations p of [n] such that p(i)-i is a multiple of eight for all i in [n].
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2
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1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 768, 2304, 6912, 20736, 62208, 186624, 559872, 1679616, 6718464, 26873856, 107495424, 429981696, 1719926784, 6879707136, 27518828544, 110075314176, 550376570880, 2751882854400, 13759414272000
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OFFSET
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0,10
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LINKS
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FORMULA
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a(n) = Product_{i=0..7} floor((n+i)/8)!.
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EXAMPLE
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a(9) = 2: 123456789, 923456781.
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MATHEMATICA
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Table[Product[Floor[(n + i)/8]!, {i, 0, 7}], {n, 0, 40}] (* Vaclav Kotesovec, Oct 02 2018 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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