1,3

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

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 159.

Sequence in context: A083227 A144072 A060570 this_sequence A090237 A138430 A164760

Adjacent sequences: A001572 A001573 A001574 this_sequence A001576 A001577 A001578

nonn

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