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A135609
a(n) = (n!)^2 - n^n.
1
0, 0, 0, 9, 320, 11275, 471744, 24578057, 1608925184, 131294473911, 13158189440000, 1593065610569389, 229433616702111744, 38775485168526047747, 7600043344545171881984, 1710011814830309043140625, 437763118250650978834448384, 126513545678306908298879235823
OFFSET
0,4
COMMENTS
a(n) > 0 for n>2.
REFERENCES
C. Smith, A Treatise on Algebra, Macmillan, London, 5th ed., 1950, p. 445.
LINKS
FORMULA
a(n) = A001044(n) - A000312(n). - Michel Marcus, Oct 23 2016
MATHEMATICA
Join[{0}, Table[(n!)^2 - n^n, {n, 1, 25}]] (* G. C. Greubel, Oct 22 2016 *)
PROG
(Magma) [Factorial(n)^2-n^n: n in [0..20]]; // Vincenzo Librandi, Oct 23 2016
(PARI) a(n) = (n!)^2 - n^n; \\ Michel Marcus, Oct 23 2016
CROSSREFS
Sequence in context: A288324 A317634 A198401 * A349287 A277422 A266065
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Mar 02 2008
STATUS
approved