http://revach.net/article.php?id=3611

Section: Moadim   Category: Hagadah Shel Pesach
Chacham Ma Hu Omer - Rav Yosef Chaim Zonnenfeld - Yaakov Tricks Eisav With The Afikoman

We tell the Chochom, "Ein Maftirin Achar HaPesach Afikoman", you cannot eat after the Afikoman.  Why this halacha?  When Eisav came in for the Brachos after Yaakov had already left and asks his father to eat his food, Yitzchok tells him, "Ba Achicha B'Mirma Vayikach Birchasecha".  Targum Yonasan ben Uziel translates this to mean, "your brother came with Chochma and received from me the Brachos." 

Rav Yosef Chaim Zonnenfeld explains what the great "chochma" was.  That night was Pesach night.  Yaakov served Yitzchok the Korban Pesach and the afikoman.  When Eisav told his father to eat the food he brought, Yitzchok said he could not do so because it is forbidden to eat after the afikoman.  This was the great chochma of Yaakov which prevented his father from partaking in Eisav's food.

Rav Yosef Chaim Zonnenfeld adds that the Gematria of B'Mirma equals 287, the same as the word... afikoman.  (Hagdah Shai LaTorah Brisk)