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!)
A028935 A006720(n)^3 (cubed terms of Somos-4 sequence). 3
1, 1, 1, 1, 8, 27, 343, 12167, 205379, 30959144, 3574558889, 553185473329, 578280195945297, 238670664494938073, 487424450554237378792, 2035972062206737347698803, 4801616835579099275862827431 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

If initial two 1's are omitted, denominator of y coordinate of (2n+1)*P where P is generator for rational points on curve y^2+y = x^3-x.

REFERENCES

B. Mazur, Arithmetic on curves, Bull. Amer Math. Soc. 14 (1986), 207-259; see p 225.

LINKS

Table of n, a(n) for n=0..16.

FORMULA

P=(0, 0), 2P=(1, 0), if kP=(a, b) then (k+1)P=(a'=(b^2-a^3)/a^2, b'=1-b*a'/a).

EXAMPLE

5P = (1/4, -5/8).

CROSSREFS

Cf. A006720, A028945, A151502.

Sequence in context: A029792 A112993 A115694 * A030089 A007235 A029789

Adjacent sequences:  A028932 A028933 A028934 * A028936 A028937 A028938

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

Edited by N. J. A. Sloane, May 14 2009

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 28 22:41 EST 2014. Contains 250439 sequences.