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Search: id:A053403
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| A053403 |
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Consider the set P of pairs (a,b) generated by the rules: (1,1) is in P; if (a,b) is in P then (b,a+b) is in P; if (a,b) and (a',b') are in P then (aa', bb') is in P. Sequence gives numbers not appearing in P. |
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+0
2
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| 7, 11, 19, 29, 31, 47, 49, 53, 67, 71, 73, 79, 87, 91, 103, 119, 127, 131, 137, 139, 141, 142, 143, 146, 147, 151, 155, 179, 191, 193, 201, 203, 211, 213, 219, 223, 227, 229, 235, 237, 239, 247, 251, 265, 271, 301, 329, 331, 337, 341, 343, 347, 355, 358, 359
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Sequence has 508 known terms, the largest of which is 55487. Conjecturally it is finite. If it is and 55487 is the largest term, then the function the number of groups of order n takes on all positive integers as values.
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REFERENCES
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R. Keith Dennis, The number of groups of order n, preprint.
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LINKS
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Index entries for groups
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CROSSREFS
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Cf. A000001, A046057.
Sequence in context: A065312 A141337 A155048 this_sequence A032672 A133425 A038984
Adjacent sequences: A053400 A053401 A053402 this_sequence A053404 A053405 A053406
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KEYWORD
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nonn,nice
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AUTHOR
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R. Keith Dennis (dennis(AT)math.cornell.edu), Jan 07 2000
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