Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A074717
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A074717 Least k such that floor(2^n/k) is prime. +0
1
1, 2, 3, 3, 6, 9, 11, 11, 7, 9, 5, 10, 19, 11, 5, 10, 9, 11, 22, 35, 39, 9, 5, 10, 20, 27, 11, 19, 9, 18, 36, 25, 29, 27, 5, 10, 20, 40, 61, 13, 21, 42, 29, 27, 39, 9, 17, 29, 58, 49, 27, 25, 50, 11, 22, 44, 39, 11, 22, 44, 29, 58, 116, 53, 19, 38, 76, 152, 237, 139, 5, 10, 20 (list; graph; listen)
OFFSET

1,2

FORMULA

There is probably a constant c such that sum(i=1, n, a(i)) is asymptotic to c*n^2 ( 0<c<1/2)

PROGRAM

(PARI) a(n)=if(n<0, 0, k=1; while(isprime(floor(2^n/k)) == 0, k++); k)

CROSSREFS

Sequence in context: A020878 A027100 A060840 this_sequence A129068 A079888 A059191

Adjacent sequences: A074714 A074715 A074716 this_sequence A074718 A074719 A074720

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Sep 04 2002

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 July 25 07:41 EDT 2008. Contains 142293 sequences.


AT&T Labs Research