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Search: id:A158279
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| A158279 |
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Number of pseudo-symmetric numerical semigroups with Frobenius number 2*n; that is, pseudo-symmetric numerical semigroups for which the largest integer not belonging to them is 2*n. |
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+0
1
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| 1, 1, 1, 2, 3, 2, 6, 7, 7, 11, 20, 14, 35, 37, 36, 70, 106, 77, 182
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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a(n)=A158206(2*n)
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REFERENCES
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J. C. Rosales, P. A. Garcia-Sanchez, J. I. Garcia-Garcia and J. A. Jimenez-Madrid, Fundamental gaps in numerical semigroups, Journal of Pure and Applied Algebra 189 (2004) 301-313.
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LINKS
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S. R. Finch, Monoids of natural numbers
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EXAMPLE
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a(3)=1: the unique pseudo-symmetric semigroup with Frobenius number 6=2*3 is generated by {4, 5, 7}.
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CROSSREFS
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Cf. A124506, A158206
Sequence in context: A144175 A077418 A005421 this_sequence A153984 A025502 A110777
Adjacent sequences: A158276 A158277 A158278 this_sequence A158280 A158281 A158282
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KEYWORD
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nonn
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AUTHOR
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S. R. Finch (Steven.Finch(AT)inria.fr), Mar 15 2009
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