login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A074753 Number of integers k such that sigma(k) < n. 5
0, 1, 1, 2, 3, 3, 4, 5, 6, 6, 6, 6, 8, 9, 10, 11, 11, 11, 13, 13, 14, 14, 14, 14, 17, 17, 17, 17, 18, 18, 19, 21, 23, 23, 23, 23, 24, 24, 25, 26, 27, 27, 30, 30, 31, 31, 31, 31, 34, 34, 34, 34, 34, 34, 36, 36, 38, 39, 39, 39, 42, 42, 43, 44, 44, 44, 44, 44, 45, 45, 45, 45, 50, 50 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..74.

FORMULA

a(n) = card( k : sigma(k) < n ); a(n) is asymptotic to c*n with c=0.67...

PROG

(PARI) a(n)=sum(i=1, n, if(1+sign(sigma(i)-n), 0, 1))

CROSSREFS

Sequence in context: A157222 A064047 A111899 * A013928 A172104 A006161

Adjacent sequences:  A074750 A074751 A074752 * A074754 A074755 A074756

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Sep 28 2002

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified March 27 22:02 EDT 2017. Contains 284182 sequences.