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 A135396 a(n) = Product_{d divides n} (n-d)!. 2
 1, 1, 2, 12, 24, 17280, 720, 87091200, 29030400, 1755758592000, 3628800, 1525930675524002119680000000, 479001600, 15033074749223731200000, 151533393472175210496000000, 2201737050440244933006930739200000000 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 LINKS G. C. Greubel, Table of n, a(n) for n = 1..100 EXAMPLE n=6, d(i)< 6 are 1;2;3; a(6)= (6-1)! * (6-2)! * (6-3)! = 17280 MAPLE A135396 := proc(n) local dvs ; dvs := numtheory[divisors](n) minus {n} ; mul( (n-i)!, i=dvs) ; end: seq(A135396(n), n=1..30) ; # R. J. Mathar, Feb 19 2008 MATHEMATICA Table[Product[(n - Divisors[n][[i]])!, {i, 1, Length[Divisors[n]]}], {n, 1, 20}] (* Stefan Steinerberger, Feb 19 2008 *) Table[Times@@((n-Divisors[n])!), {n, 20}] (* Harvey P. Dale, Dec 10 2014 *) PROG (PARI) a(n)=my(s=1); fordiv(n, d, s*=(n-d)!); s \\ Charles R Greathouse IV, Oct 12 2016 CROSSREFS Cf. A000142. Sequence in context: A232248 A091137 A092825 * A031048 A294554 A098707 Adjacent sequences:  A135393 A135394 A135395 * A135397 A135398 A135399 KEYWORD easy,nonn AUTHOR Ctibor O. Zizka, Feb 17 2008 EXTENSIONS Definition simplified by Stefan Steinerberger, Feb 19 2008 More terms from R. J. Mathar and Stefan Steinerberger, Feb 19 2008 STATUS approved

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Last modified October 18 07:19 EDT 2019. Contains 328146 sequences. (Running on oeis4.)