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

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A112674 Numbers of the form (2^(i*j)-1)/((2^i-1)*(2^j-1)) where gcd(i,j) = 1. 0
1, 3, 11, 39, 43, 151, 171, 683, 2255, 2359, 2731, 9399, 10923, 43691, 140911, 149943, 174763, 549791, 599479, 699051, 2796203, 8727391, 8965359, 9588151, 11184811, 38350263, 44739243, 139090655, 178956971, 549687103, 572942063, 613576119 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

REFERENCES

C. L. Chen, R. T. Chien and C. K. Liu, On the binary representation form of certain integers, SIAM J. Appl. Math. 26 (1974), 283-293.

LINKS

Table of n, a(n) for n=1..32.

MATHEMATICA

t = {1}; Do[a = (2^(i*j) - 1)/((2^i - 1)*(2^j - 1)); If[ GCD[i, j] == 1 && 1 < a < 10^9, AppendTo[t, a]], {i, 31}, {j, i - 1}]; Sort@t (* Robert G. Wilson v *)

CROSSREFS

Sequence in context: A178624 A027528 A192528 * A064086 A089579 A227638

Adjacent sequences:  A112671 A112672 A112673 * A112675 A112676 A112677

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 30 2005

EXTENSIONS

More terms from Robert G. Wilson v, Dec 31 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified November 24 18:35 EST 2014. Contains 249909 sequences.