1,1

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. L. Graham, D. E. Knuth and O. Patashnik, Concrete Mathematics. Addison-Wesley, Reading, MA, 1990, p. 254.

J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 125.

N. J. A. Sloane, An on-line version of the Encyclopedia of Integer Sequences, Electronic J. Combinatorics, Vol. 1, no. 1, 1994.

Sequence in context: A067107 A047690 A113569 this_sequence A046857 A129454 A140258

Adjacent sequences: A007335 A007336 A007337 this_sequence A007339 A007340 A007341

nonn

N. J. A. Sloane (njas(AT)research.att.com).

Last term corrected Mar 15 1997 by Olivier Gerard.