In VN’s novel Lolita (1955) the number 342 reappears three times. 342 Lawn Street is the address of the Haze house in Ramsdale. 342 is Humbert Humbert's and Lolita's room in The Enchanted Hunters (a hotel in Briceland where they spend their first night together). According to Humbert Humbert, between July 5 and November 18, 1949, he registered (if not actually stayed) at 342 hotels, motels and tourist homes.
All the main characters in Lolita die in 1952. 1952 was a leap year. In a leap year there are 366 days. There are 24 hours in a day. 366 – 24 = 342. Humbert Humbert meets Lolita in 1947, twenty-four years after his childhood romance with Annabel Leigh (who must have died on Dec. 7, 1923, the 342nd day of the year).
In his essay Vremya – mera mira (“Time is the Measure of the Universe,” 1916) Velimir Khlebnikov says that there are two sacred numbers: 365 (the number of days in a non-leap year) and 317, Khlebnikov’s personal sacred number (according to Khlebnikov, he was one of the 317 chairmen of the world; besides, 317 years is a period between large naval battles). Between Pushkin's engagement (April 6, 1830) and his wedding (February 18, 1831) passed 317 days.
365 – 317 = 48 (24 + 24). In 1912 Khlebnikov, using his calculations, predicted the 1917 Revolution.
According to John Ray, Jr., Humbert Humbert died on November 16, 1952. In leap years November 16 is the 321st day of the year. 321 + 21 (three weeks) = 342. According to Humbert Humbert, it took him fifty-six days (eight weeks) to write Lolita:
When I started, fifty-six days ago, to write Lolita, first in the psychopathic ward for observation, and then in this well-heated, albeit tombal, seclusion, I thought I would use these notes in toto at my trial, to save not my head, of course, but my soul. In mind-composition, however, I realized that I could not parade living Lolita. I still may use parts of this memoir in hermetic sessions, but publication is to be deferred. (2.36)
Btw., in his essay Zakon pokoloeniy ("The Law of Generations," 1914) Khlebnikov mentions the real Pnin and his year of birth: 1773:
Пнин 1773 и Панин 1801 (отношение к крепостному праву).