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 A171163 Number of children at height n in a doubly logarithmic tree. Leaves are at height 0. 1
 0, 2, 2, 4, 16, 256, 65536, 4294967296, 18446744073709551616, 340282366920938463463374607431768211456, 115792089237316195423570985008687907853269984665640564039457584007913129639936 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..13 Omer Berkman, Baruch Schieber and Uzi Vishkin, Optimal doubly logarithmic parallel algorithms based on finding all nearest smaller values, Journal of Algorithms, 14(1993)(3): 344-370. FORMULA a(0)=0, a(1)=2; for n>1, a(n) = 2^(2^(n-2)). MATHEMATICA Join[{0, 2}, Table[2^2^(n-2), {n, 2, 9}]] (* Harvey P. Dale, Feb 01 2014 *) PROG (Python) def doubly_log_tree_children(n): if n==0: return 0 if n==1: return 2 return 2**(2**(n-2)) CROSSREFS Equals A001146 with the prefix 0, 2. Cf. A165420. [R. J. Mathar, Dec 11 2009] Sequence in context: A168088 A168089 A165420 * A129614 A070283 A070282 Adjacent sequences: A171160 A171161 A171162 * A171164 A171165 A171166 KEYWORD nonn AUTHOR Chad Brewbaker, Dec 04 2009 EXTENSIONS More terms from Harvey P. Dale, Feb 01 2014 STATUS approved

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Last modified June 19 22:07 EDT 2024. Contains 373507 sequences. (Running on oeis4.)