OFFSET
1,3
LINKS
V. A. Liskovets, Some easily derivable sequences, J. Integer Sequences, 3 (2000), #00.2.2.
FORMULA
a(n) = (A007080(n) - n!)/2. - Andrew Howroyd, Sep 10 2018
MATHEMATICA
a[n_] := (A007080[[n]] - n!)/2;
Array[a, 14] (* Jean-François Alcover, Aug 27 2019 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, May 24 2000
EXTENSIONS
More terms from Vladeta Jovovic, Mar 05 2001
a(12)-a(14) from Andrew Howroyd, Sep 10 2018
STATUS
approved