Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A153823
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A153823 Number of proper divisors of n!. +0
2
0, 0, 1, 3, 7, 15, 29, 59, 95, 159, 269, 539, 791, 1583, 2591, 4031, 5375, 10751, 14687, 29375, 41039, 60799, 95999, 191999, 242879, 340031, 532223, 677375, 917279, 1834559, 2332799, 4665599, 5529599, 7864319, 12165119, 16422911 (list; graph; listen)
OFFSET

0,4

COMMENT

a(n) is the number of proper divisors of factorial number A000142(n).

FORMULA

a(n) = A000005(A000142(n))-1 = A032741(A000142(n)) = A027423(n)-1.

CROSSREFS

Cf. A000005, A000142, A027423, A032741.

Cf. A153823, A153825. [From Omar E. Pol (info(AT)polprimos.com), Jan 17 2009]

Sequence in context: A023608 A132780 A018087 this_sequence A080011 A120538 A146019

Adjacent sequences: A153820 A153821 A153822 this_sequence A153824 A153825 A153826

KEYWORD

nonn

AUTHOR

Omar E. Pol (info(AT)polprimos.com), Jan 02 2009

EXTENSIONS

More terms from Omar E. Pol (info(AT)polprimos.com), Jan 17 2009

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified December 11 12:57 EST 2009. Contains 170656 sequences.


AT&T Labs Research