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A173506
a(n) = (3^(3^n) - 1)/2.
1
1, 13, 9841, 3812798742493, 221713244121518884974124815309574946401
OFFSET
0,2
LINKS
FORMULA
2*a(n+1) + 1 = ( 2*a(n) + 1 )^3.
MATHEMATICA
Table[(3^(3^m) -1)/2, {m, 0, 10}]
PROG
(Sage) [(3^(3^n) -1)/2 for n in (0..10)] # G. C. Greubel, Apr 25 2021
CROSSREFS
Sequence in context: A208169 A205162 A122429 * A173840 A260457 A219315
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Feb 20 2010
EXTENSIONS
Introduced standard nomenclature in the definition, added recurrence - the Assoc. Editors of the OEIS, Feb 24 2010
STATUS
approved