

A003160


a(1)=a(2)=1, a(n)=na(a(n1))a(a(n2)).
(Formerly M0446)


5



1, 1, 1, 2, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 8, 9, 9, 9, 10, 11, 12, 12, 12, 13, 14, 15, 15, 15, 16, 16, 16, 17, 17, 17, 18, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, 28, 29, 30, 30, 30, 31, 32, 33, 33, 33, 34, 35, 36, 36, 36, 37, 37, 37, 38
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OFFSET

1,4


COMMENTS

Sequence of indices n where a(n1)<a(n) appears to be given by A003156. [From Joerg Arndt, May 11 2010]


REFERENCES

L. Carlitz, R. Scoville and V. E. Hoggatt, Jr., Representations for a special sequence, Fib. Quart., 10 (1972), 499518, 550.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


FORMULA

a(n) is asymptotic to n/2.


PROG

(PARI) a(n)=if(n<3, 1, na(a(n1))a(a(n2)))
(Haskell)
a003160 n = a003160_list !! (n1)
a003160_list = 1 : 1 : zipWith () [3..] (zipWith (+) xs $ tail xs)
where xs = map a003160 a003160_list
 Reinhard Zumkeller, Aug 02 2013


CROSSREFS

Cf. A005206.
Cf. A095774, A095775.
Sequence in context: A239683 A132913 A278814 * A060740 A145339 A123273
Adjacent sequences: A003157 A003158 A003159 * A003161 A003162 A003163


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

Edited by Benoit Cloitre, Jan 01 2003


STATUS

approved



