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A282181 a(n+1) = a(n)*(a(n)^2 - 3) with a(0) = 9. 1
9, 702, 345946302, 41402453463588423862656702, 70970560162990674076135964501350282214065161983319841388247466125133356250302 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

LINKS

Table of n, a(n) for n=0..4.

E. B. Escott, Rapid method for extracting a square root, Amer. Math. Monthly, 44 (1937), 644-646.

FORMULA

a(n) = ((9 + sqrt(77))/2)^(3^n) + ((9 - sqrt(77))/2)^(3^n). - Bruno Berselli, Feb 10 2017

MATHEMATICA

RecurrenceTable[{a[0] == 9, a[n] == a[n-1]^3 - 3 a[n-1]}, a, {n, 8}]

PROG

(MAGMA) [n eq 1 select 9 else Self(n-1)^3-3*Self(n-1): n in [1..6]];

CROSSREFS

Cf. similar sequences listed in A282180.

Sequence in context: A059492 A322488 A109061 * A053515 A120816 A161585

Adjacent sequences:  A282178 A282179 A282180 * A282182 A282183 A282184

KEYWORD

nonn

AUTHOR

Vincenzo Librandi, Feb 10 2017

STATUS

approved

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Last modified September 15 12:22 EDT 2019. Contains 327078 sequences. (Running on oeis4.)