OFFSET
1,4
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
W. F. Lunnon, Counting multidimensional polyominoes. Computer Journal 18 (1975), no. 4, pp. 366-367.
FORMULA
MATHEMATICA
a /@ Range[1, 19] (* Jean-François Alcover, Sep 22 2019 *)
CROSSREFS
KEYWORD
nonn,more
AUTHOR
EXTENSIONS
More terms from Jean-François Alcover, Sep 22 2019
STATUS
approved