Anderson Cooper and pal Benjamin Maisani, owner of East Village bar Eastern Bloc, took a group to Serendipity 3 the other day. Cooper and Maisani both ordered foot-long hot dogs and Frrrozen Hot Chocolate. Cooper requested the “Warhol” table where his mom, Gloria Vanderbilt, used to hold court with Andy Warhol and friends. A Serendipity source said it’s the table where Vanderbilt would sit with Cooper as a kid.