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Search: id:A064381
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| A064381 |
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Number of subsets of {2,..n} such that product of their elements is congruent to 0 (mod n+1). |
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+0
1
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| 0, 0, 0, 6, 0, 24, 32, 120, 0, 792, 0, 2016, 5760, 13056, 0, 55136, 0, 226944, 387072, 523776, 0, 4112000, 5767168
(list; graph; listen)
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OFFSET
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2,4
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COMMENT
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a(n-1) = 0 for prime n.
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EXAMPLE
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a(5)=6 because there are 6 subsets of {2,3,4,5} such that product of their elements is congruent to 0 (mod 6): {3,4,5}, {2,3,4,5}, {3,4}, {2,3}, {2,3,4}, {2,3,5}.
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CROSSREFS
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Cf. A000048.
Sequence in context: A057401 A019134 A082731 this_sequence A062254 A028849 A138704
Adjacent sequences: A064378 A064379 A064380 this_sequence A064382 A064383 A064384
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KEYWORD
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nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)Eunet.yu), Sep 27 2001
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EXTENSIONS
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More terms from Naohiro Nomoto (n_nomoto(AT)yabumi.com), Oct 01 2001
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