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

 

Logo

Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.

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 September 18 05:49 EDT 2014. Contains 246893 sequences.