
REFERENCES

Chung, F. R. K.; Graham, R. L.; Pippenger, N. On graphs which contain all small trees. II. Combinatorics (Proc. Fifth Hungarian Colloq., Keszthely, 1976), Vol. I, pp. 213223. Colloq. Math. Soc. Janos Bolyai, 18. NorthHolland, Amsterdam, 1978.
R. L. Graham, personal communication.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
