

A007672


a(n) = A002034(n)!/n.
(Formerly M1669)


5



1, 1, 2, 6, 24, 1, 720, 3, 80, 12, 3628800, 2, 479001600, 360, 8, 45, 20922789888000, 40, 6402373705728000, 6, 240, 1814400, 1124000727777607680000, 1, 145152, 239500800, 13440, 180, 304888344611713860501504000000
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OFFSET

1,3


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Table of n, a(n) for n=1..29.
A. J. Kempner, Miscellanea, Amer. Math. Monthly, 25 (1918), 201210 [ See Section II, "Concerning the smallest integer m! divisible by a given integer n". ]


MATHEMATICA

a[n_] := Module[{m = 1, x = n, as = 1, p}, While[x > 1, m++; p = GCD[x, m]; x = x/p; as *= m/p]; as]; Array[a, 30] (* JeanFrançois Alcover, May 09 2017, after Antonio Roldán *)


PROG

(PARI) a(n)={local(m=1, x=n, as=1, p); while(x>1, m++; p=gcd(x, m); x=x/p; as*=m/p); as} \\ Antonio Roldán, Apr 04 2015


CROSSREFS

Sequence in context: A327426 A086554 A213324 * A322255 A084337 A323615
Adjacent sequences: A007669 A007670 A007671 * A007673 A007674 A007675


KEYWORD

nonn,nice


AUTHOR

N. J. A. Sloane, Robert G. Wilson v


STATUS

approved



