1,1

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

V. Reddy and S. Skiena, Frequencies of large distances in integer lattices, in Graph theory, combinatorics and algoithms, Vol. 1, 2 (Kalamazoo, MI, 1992), 981-989, Wiley-Intersci. Publ., Wiley, New York, 1995.

Cf. A007543.

Sequence in context: A137980 A144137 A166727 this_sequence A048188 A121024 A120622

Adjacent sequences: A007541 A007542 A007543 this_sequence A007545 A007546 A007547

nonn

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