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A139173
a(n) = n!/3 - 1.
9
1, 7, 39, 239, 1679, 13439, 120959, 1209599, 13305599, 159667199, 2075673599, 29059430399, 435891455999, 6974263295999, 118562476031999, 2134124568575999, 40548366802943999, 810967336058879999
OFFSET
3,2
COMMENTS
Original definition: Natural numbers of the form (n! - 3)/3.
LINKS
FORMULA
E.g.f.: (6 - 3*x^2 - x^3)/(6*(1-x)) - exp(x). - G. C. Greubel, Oct 18 2018
MATHEMATICA
Table[(n! - 3)/3, {n, 3, 20}]
PROG
(Magma) [Factorial(n)/3 -1: n in [3..25]]; // Vincenzo Librandi, Jul 20 2011
(PARI) for(n=3, 25, print1((n!-3)/3, ", ")) \\ G. C. Greubel, Oct 18 2018
CROSSREFS
Cf. A139191: primes in this sequence. - M. F. Hasler, Apr 09 2009
Sequence in context: A122884 A375997 A370228 * A219437 A219138 A365485
KEYWORD
nonn
AUTHOR
Artur Jasinski, Apr 11 2008
EXTENSIONS
Edited by M. F. Hasler, Apr 09 2009
STATUS
approved