This was one of the last illustrations cut from Strike from the Sea to make the limit. Provided by the Grumman Historical Center, it depicts a single-seat A-6 providing close air support to the Marines. The proposal was in response to a 1962 Navy requirement to replace the single-seat Douglas A-1 (AD) Skyraider. (The two-seat A-6 had replaced the A-1G (AD-5N) night attack variant.) Also see http://thanlont.blogspot.com/2008/08/single-seat-6.html
Unfortunately, the Navy had in mind not only a variant of an existing aircraft, but one powered by a single TF30 turbofan engine, which not coincidentally at the time was also the basic powerplant for the nascent Grumman/General Dynamics F-111B. Grumman management was forced to choose between full compliance, a TF30-powered F-11 (F11F) Tiger—don't scoff, the winner of the competition was Vought's proposal, which closely resembled the Vought F-8 (F8U) Crusader)—and a proposal that they hoped the Navy would realize was a better deal than an all-but-new design powered by a new engine. They were wrong, although their Attack Tiger would probably have lost to Vought's excellent proposal anyway, as did Douglas' proposal of an A-4 (A4D) Skyhawk on steroids. For more, see chapter nine in my book on U.S. Navy attack aircraft, Strike from the Sea.