The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A090618 Highest power of 9 dividing n!. 3
 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 7, 7, 8, 8, 8, 9, 9, 9, 9, 9, 9, 10, 10, 10, 11, 11, 11, 11, 11, 11, 13, 13, 13, 13, 13, 13, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 17, 17, 17, 17, 17, 17, 18, 18, 18, 20, 20, 20, 20 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,10 LINKS FORMULA a(n) =A090622(n, 9) =[A054861(n)/2] =[([n/3]+[n/9]+[n/27]+[n/81]+...)/2]. EXAMPLE a(9)=2 since 9!=362880=9^2*4480. MATHEMATICA IntegerExponent[Range[0, 90]!, 9] (* Harvey P. Dale, Jun 07 2016 *) CROSSREFS Cf. A011371, A054861, A090616, A027868, A054896, A090617. Sequence in context: A280952 A235122 A131996 * A186444 A072748 A174631 Adjacent sequences:  A090615 A090616 A090617 * A090619 A090620 A090621 KEYWORD nonn AUTHOR Henry Bottomley, Dec 06 2003 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 12 17:17 EDT 2020. Contains 336439 sequences. (Running on oeis4.)