

A244478


a(0)=2, a(1)=0, a(2)=2; thereafter a(n) = a(n1a(n1))+a(n2a(n2)) unless a(n1) <= n1 or a(n2) <= n2 in which case the sequence terminates.


3



2, 0, 2, 2, 2, 2, 4, 4, 4, 4, 4, 6, 6, 6, 8, 8, 8, 8, 8, 8, 10, 10, 10, 12, 12, 12, 12, 14, 14, 14, 16, 16, 16, 16, 16, 16, 16, 18, 18, 18, 20, 20, 20, 20, 22, 22, 22, 24, 24, 24, 24, 24, 26, 26, 26, 28, 28, 28, 28, 30, 30, 30, 32, 32, 32, 32, 32, 32, 32, 32, 34, 34, 34, 36, 36, 36, 36, 38, 38, 38
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OFFSET

0,1


REFERENCES

Higham, J.; Tanny, S. More wellbehaved metaFibonacci sequences. Proceedings of the Twentyfourth Southeastern International Conference on Combinatorics, Graph Theory, and Computing (Boca Raton, FL, 1993). Congr. Numer. 98(1993), 317. See Prop. 2.1.


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000
Index entries for Hofstadtertype sequences


MAPLE

f := proc(n) option remember;
if n=0 then 2
elif n=1 then 0
elif n=2 then 2
else
f(n1f(n1))+f(n2f(n2));
fi;
end proc;
[seq(f(n), n=0..2000)];


PROG

(Haskell)
a244478 n = a244478_list !! n
a244478_list = 2 : 0 : 2 : zipWith (+) xs (tail xs)
where xs = map a244478 $ zipWith () [1..] $ tail a244478_list
 Reinhard Zumkeller, Jul 05 2014


CROSSREFS

A006949, A240807, A240808 use the same recurrence.
See also A244479 (a(n)/2).
Sequence in context: A161872 A278248 A036461 * A261153 A199123 A291308
Adjacent sequences: A244475 A244476 A244477 * A244479 A244480 A244481


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Jul 02 2014


STATUS

approved



