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A114957
a(n) = ceiling(a(n-1)^(4/3) + a(n-2)^(4/3)), with a(0) = a(1) = 1.
0
1, 1, 2, 4, 9, 26, 96, 517, 4589, 80409, 3546873, 544383737, 445042712531, 3398279290987133, 510914600201184438040, 4084427005585662985398294639, 6528922582874884079540382952631569851, 12202683821888699966029264978793346242448495941305
OFFSET
0,3
EXAMPLE
a(2) = ceiling(a(0)^(4/3) + a(1)^(4/3)) = ceiling(1^(4/3) + 1^(4/3)) = 2.
a(3) = ceiling(a(1)^(4/3) + a(2)^(4/3)) = ceiling(1^(4/3) + 2^(4/3)) = ceiling(3.5198421) = 4.
a(4) = ceiling(2^(4/3) + 4^(4/3)) = ceiling(8.86944631) = 9.
a(5) = ceiling(4^(4/3) + 9^(4/3)) = ceiling(25.0703586) = 26.
a(6) = ceiling(9^(4/3) + 26^(4/3)) = ceiling(95.7456522) = 96.
a(7) = ceiling(26^(4/3) + 96^(4/3)) = ceiling(516.595167) = 517.
a(8) = ceiling(96^(4/3) + 517^(4/3)) = ceiling(4588.99022) = 4589.
MATHEMATICA
Nest[Append[#, Ceiling[Total[Take[#, -2]^(4/3)]]]&, {1, 1}, 17] (* Harvey P. Dale, Apr 21 2011 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Jonathan Vos Post, Feb 21 2006
EXTENSIONS
Corrected and extended by Harvey P. Dale, Apr 21 2011
Comments edited by Petros Hadjicostas, Nov 03 2019
STATUS
approved