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

 

Logo

Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 5000 articles have referenced us, often saying "we discovered this result with the help of the OEIS".

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A028939 a(n) = denominator of y-coordinate of (2n)*P where P is the generator for rational points on the curve y^2 + y = x^3 - x. 6
1, 1, 1, 125, 64, 24389, 2146689, 274625, 50202571769, 4302115807744, 1469451780501769, 13528653463047586625, 343216282443844010111, 63061816101171948456692661, 495133617181351428873673516736 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Seiichi Manyama, Table of n, a(n) for n = 1..86

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

a(n) = A028943(2n). - Seiichi Manyama, Nov 19 2016

EXAMPLE

8P = (21/25, -69/125).

CROSSREFS

Cf. A028936, A028937, A028938 (numerator), A028943.

Sequence in context: A077495 A030668 A030678 * A195420 A080538 A104233

Adjacent sequences:  A028936 A028937 A028938 * A028940 A028941 A028942

KEYWORD

nonn,frac

AUTHOR

N. J. A. Sloane

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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy .

Last modified December 6 15:25 EST 2016. Contains 278781 sequences.