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A028939 Denominator of y coordinate of (2n)*P where P is generator for rational points on curve y^2+y = x^3-x. 2
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

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=1..15.

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

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

CROSSREFS

Sequence in context: A077495 A030668 A030678 * A195420 A080538 A104233

Adjacent sequences:  A028936 A028937 A028938 * A028940 A028941 A028942

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified December 21 06:19 EST 2014. Contains 252297 sequences.