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A158206 Number of irreducible numerical semigroups with Frobenius number n; that is, irreducible numerical semigroups for which the largest integer not belonging to them is n. 3
1, 1, 1, 1, 2, 1, 3, 2, 3, 3, 6, 2, 8, 6, 7, 7, 15, 7, 20, 11, 18, 20, 36, 14, 44, 35, 45, 37, 83, 36, 109, 70, 101, 106, 174, 77, 246, 182, 227 (list; graph; refs; listen; history; internal format)
OFFSET

1,5

REFERENCES

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.

LINKS

S. R. Finch, Monoids of natural numbers

EXAMPLE

a(5)=2: the 2 irreducible semigroups generated by {3, 4} and {2, 7} have Frobenius number 5.

CROSSREFS

Cf. A124506

Sequence in context: A053262 A007359 A174427 * A164988 A201592 A115872

Adjacent sequences:  A158203 A158204 A158205 * A158207 A158208 A158209

KEYWORD

nonn

AUTHOR

S. R. Finch (Steven.Finch(AT)inria.fr), Mar 13 2009

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Last modified February 15 09:00 EST 2012. Contains 205746 sequences.