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A174677 a(n) = 2*a(n-1)*a(n-2) with a(0)=1 and a(1)=1. 3
1, 1, 2, 4, 16, 128, 4096, 1048576, 8589934592, 18014398509481984, 309485009821345068724781056, 11150372599265311570767859136324180752990208 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

a(n) = 2^(Fibonacci(n+1)-1).

a(n) = 1/2 * A000301(n+1).

a(n) is the number of node minimal AVL trees of height n. - Alois P. Heinz, Mar 13 2013

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..17

MATHEMATICA

Join[{a=1, b=2}, Table[c=2*a*b; a=b; b=c, {n, 12}]] (* Vladimir Joseph Stephan Orlovsky, Apr 19 2011 *)

RecurrenceTable[{a[1]==1, a[2]==2, a[n]==2a[n-1]a[n-2]}, a[n], {n, 12}] (* Harvey P. Dale, Jul 07 2011 *)

PROG

(MAGMA) [(2^(Fibonacci(n+1)-1): n in [1..10]]; // Vincenzo Librandi, Apr 24 2011

CROSSREFS

Cf. A174666, A000045, A000301, A143897, A217298.

Sequence in context: A144526 A179532 A217994 * A073924 A061588 A202360

Adjacent sequences:  A174674 A174675 A174676 * A174678 A174679 A174680

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Mar 26 2010

EXTENSIONS

Formula index corrected by R. J. Mathar, Mar 30 2010

a(0)=1 prepended and name edited by Alois P. Heinz, Jul 05 2021

STATUS

approved

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Last modified October 20 10:43 EDT 2021. Contains 348100 sequences. (Running on oeis4.)