

A285763


a(n) = a(a(n  2)) + a(n  a(n  2)), with a(1) = 1, a(2) = a(3) = a(4) = 2, a(5) = 3.


2



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

1,2


COMMENTS

The sequence a(n) is monotonic, with successive terms increasing by 0 or 1. So the sequence hits every positive integer.
This sequence can be obtained from the HofstadterConway sequence A004001 using a construction of Isgur et al.


LINKS

Nathan Fox, Table of n, a(n) for n = 1..10000
A. Isgur, R. Lech, S. Moore, S. Tanny, Y. Verberne, and Y. Zhang, Constructing New Families of Nested Recursions with Slow Solutions, SIAM J. Discrete Math., 30(2), 2016, 11281147. (20 pages); DOI:10.1137/15M1040505


MAPLE

A285763:=proc(n) option remember: if n <= 0 then 0: elif n = 1 then 1: elif n = 2 then 2: elif n = 3 then 2: elif n = 4 then 2: elif n = 5 then 3: else A285763(A285763(n2)) + A285763(nA285763(n2)): fi: end:


MATHEMATICA

a[1] = 1; a[2] = a[3] = a[4] = 2; a[5] = 3; a[n_] := a[n] = a[a[n  2]] + a[n  a[n  2]]; Array[a, 64] (* Michael De Vlieger, Apr 26 2017 *)


CROSSREFS

Cf. A004001, A285764.
Sequence in context: A126257 A025773 A308303 * A294621 A029077 A112176
Adjacent sequences: A285760 A285761 A285762 * A285764 A285765 A285766


KEYWORD

nonn


AUTHOR

Nathan Fox, Apr 25 2017


STATUS

approved



