On Sunday, Lincoln Center Out of Doors hosted the third of five days of “New York City Honors Pete Seeger,” or Seegerfest, as the events are called. This was the festival’s main event. A concert featured artists singing songs Seeger was associated with, like “The Hammer Song,” “Turn, Turn, Turn,” and, of course, “Where Have All the Flowers Gone?” The artists included old-time folkies like Judy Collins, who opened the program, Fred Hellerman of The Weavers, the popular children’s singer Dan Zanes, banjo master Tony Trischka, Tom Chapin and the Chapin sisters, and Jay Ungar and Molly Mason. The artists...