OFFSET
1,2
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
M. C. Wunderlich, The improbable behavior of Ulam's summation sequence, pp. 249-257 of A. O. L. Atkin and B. J. Birch, editors, Computers in Number Theory. Academic Press, NY, 1971.
LINKS
R. G. Wilson, V, Letter to N. J. A. Sloane, Sep. 1992
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved