

A028935


a(n) = A006720(n)^3 (cubed terms of Somos4 sequence).


5



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 ycoordinate of (2n+1)*P where P is the generator for rational points on the curve y^2 + y = x^3  x.


LINKS

Seiichi Manyama, Table of n, a(n) for n = 0..88
B. Mazur, Arithmetic on curves, Bull. Amer. Math. Soc. 14 (1986), 207259; see p. 225.


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, A028934, A028943, A028945, A151502.
Sequence in context: A029792 A112993 A115694 * A030089 A007235 A029789
Adjacent sequences: A028932 A028933 A028934 * A028936 A028937 A028938


KEYWORD

nonn,changed


AUTHOR

N. J. A. Sloane


EXTENSIONS

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


STATUS

approved



