A156821 Prime factors of 13! listed with multiplicity.

2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 5, 5, 7, 11, 13

Offset

1,1

Links

Table of n, a(n) for n=1..20.

Example

13! = 2^10 * 3^5 * 5^2 * 7 * 11 * 13.
From Vincenzo Librandi, Jun 13 2014: (Start)
Floor(13/2) = 6, floor(13/4) = 3, floor(13/8) = 1; 6 + 3 + 1 = 10 -> 2^10.
Floor(13/3) = 4, floor(13/9) = 1; 4 + 1 = 5 -> 3^5.
Floor(13/5) = 2 -> 5^2.
Floor(13/7) = 1 -> 7.
Floor(13/11) = 1 -> 11.
13/13 = 1 -> 13. (End)

Mathematica

Flatten[Table[#[[1]], {#[[2]]}] & /@ FactorInteger[13!]] (* Alonso del Arte, Jun 14 2014, based on Jean-François Alcover's program for A027746 *)

Crossrefs

Sequence in context: A061217 A102684 A337637 * A025856 A350765 A103378

Adjacent sequences: A156818 A156819 A156820 * A156822 A156823 A156824

Keyword

nonn,fini,full

Author

Vincenzo Librandi, Feb 16 2009

Extensions

Edited for clarity by Jon E. Schoenfield, Jun 18 2010

Status

approved