The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 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 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.

Last modified May 13 18:37 EDT 2021. Contains 343868 sequences. (Running on oeis4.)