

A063917


Smallest k such that k!!! is a multiple of n.


3



1, 2, 3, 4, 5, 6, 7, 8, 6, 5, 11, 12, 13, 7, 15, 8, 17, 6, 19, 8, 21, 11, 23, 12, 20, 13, 9, 7, 29, 15, 31, 14, 33, 17, 10, 12, 37, 19, 39, 8, 41, 21, 43, 11, 15, 23, 47, 18, 28, 20, 51, 13, 53, 9, 11, 10, 57, 29, 59, 15, 61, 31, 21, 16, 13, 33, 67, 17, 69
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OFFSET

1,2


REFERENCES

F. Smarandache, "Some problems in number theory", Student Conference, University of Craiova, Department of Mathematics, 1979.


LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..2000
Anonymous, Smarandache kfactorial


EXAMPLE

a(16) = 8 because 8!!! = 8*(8  3)*(8  6) = 8*5*2 which is divisible by 16 and 8 is the smallest integer with this property.


MATHEMATICA

f[n_] := Product[k, {k, n, 1, 3}]; a[n_] := Module[{k = 1}, While[! Divisible[ f[k], n], k++]; k]; Array[a, 100] (* Amiram Eldar, Dec 08 2018 *)
With[{tbl=Table[Times@@Range[k, 1, 3], {k, 100}]}, Table[Position[tbl, _?(Divisible[ #, n]&), 1, 1], {n, 70}]]//Flatten (* Harvey P. Dale, Feb 11 2020 *)


CROSSREFS

Cf. A007661.
Sequence in context: A245354 A097377 A234741 * A234344 A331298 A325351
Adjacent sequences: A063914 A063915 A063916 * A063918 A063919 A063920


KEYWORD

nonn


AUTHOR

Mike Antholy (mikeantholy(AT)yahoo.ca), Aug 31 2001


EXTENSIONS

Offset changed and more terms by Amiram Eldar, Dec 08 2018


STATUS

approved



