. Proof, If ? < 4, then S satisfies Wilf's Conjecture ([3]). Hence, we can suppose that ? ? 4. Thus

]. V. Barucci, On propinquity of numerical semigroups and one-dimensional local Cohen Macaulay rings, Journal of Commutative algebra and its applications, Proceedings of the Fifth International Fez Conference on Commutative Algebra and Applications, pp.49-60, 2009.

M. Bras-amorós, Fibonacci-like behavior of the number of numerical semigroups of a given genus, Semigroup Forum, vol.85, issue.7, pp.379-384, 2008.
DOI : 10.1007/s00233-007-9014-8

D. Dobbs and G. Matthews, On a question of Wilf concerning numerical semigroups, Focus on commutative rings research, pp.193-202, 2006.

S. Eliahou, Wilf's Conjecture and Macaulay's theorem, preprint

R. Fröberg, C. Gottlieb, and R. Häggkvist, On numerical semigroups, Semigroup forum, pp.63-83, 1986.
DOI : 10.1007/BF02573091

N. Kaplan, Counting numerical semigroups by genus and some cases of a question of Wilf, Journal of Pure and Applied Algebra, vol.216, issue.5, pp.1016-1032, 2012.
DOI : 10.1016/j.jpaa.2011.10.038

P. A. García-sánchez and J. C. Rosales, Numerical semigroups, Developments in Mathematics, vol.20, 2009.

A. Sammartano, Numerical semigroups with large embedding dimension satisfy Wilf's conjecture, Semigroup Forum, pp.439-447, 2012.

J. J. Sylvester, Mathematical questions with their solutions, Educational Times, vol.41, p.21, 1884.

H. S. Wilf, A Circle-Of-Lights Algorithm for the "Money-Changing Problem", The American Mathematical Monthly, vol.85, issue.7, pp.562-565, 1978.
DOI : 10.2307/2320864

A. Zhai, An asymptotic result concerning a question of Wilf, 2011.