摘要
The original version of the article was published in [1]. Unfortunately, the original version of this article contains a mistake： in Theorem 6.2 appears that β（n, △） = （n-△ ＋ 5）/4 but the correct statement is β（n, △） = （n -△ ＋ 4）/4. In this erratum we correct the theorem and give the correct proof.
The original version of the article was published in [1]. Unfortunately, the original version of this article contains a mistake： in Theorem 6.2 appears that β（n, △） = （n-△ ＋ 5）/4 but the correct statement is β（n, △） = （n -△ ＋ 4）/4. In this erratum we correct the theorem and give the correct proof.
基金
Supported by two grants from Ministerio de Economía y Competitividad,Spain(Grant Nos.MTM2013-46374-P and MTM2015-69323-REDT)
