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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A071603 Number of different positive integers that we can obtain by using the integers {1,2,...,n} using each number at most once and the operators +, -, *, /. 0
1, 3, 9, 31, 121, 542, 2868, 16329, 106762 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..9.

Index entries for similar sequences

EXAMPLE

a(4)=31 because we can obtain the positive integers 1,2,...,28 and 30,32,36 by using the integers {1, 2, 3, 4} at most once and the four operations. For example 30 = 3*2*(4+1)

CROSSREFS

Cf. A060315, A070960.

Sequence in context: A086616 A040027 A182968 * A090595 A027040 A111063

Adjacent sequences:  A071600 A071601 A071602 * A071604 A071605 A071606

KEYWORD

more,nonn

AUTHOR

Koksal Karakus (karakusk(AT)hotmail.com), Jun 02 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
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 14 14:45 EDT 2019. Contains 328019 sequences. (Running on oeis4.)