OFFSET
1,2
REFERENCES
J. P. Gram, Undersoegelser angaaende maengden af primtal under en given graense, Det Kongelige Danskevidenskabernes Selskabs Skrifter, series 6, vol. 2 (1884), 183-288; see p. 255.
N. J. A. Sloane, A Handbook of Integer Sequences, Entry 565, Academic Press, 1973.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Entry M1431, Academic Press, 1995.
CROSSREFS
KEYWORD
dead
STATUS
approved