A283893 Relative of Hofstadter Q-sequence: a(1) = 3, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

3, 2, 3, 5, 2, 8, 2, 8, 5, 4, 10, 10, 6, 13, 7, 8, 9, 9, 8, 20, 9, 8, 20, 13, 12, 19, 15, 11, 22, 16, 12, 28, 11, 28, 15, 17, 28, 13, 29, 25, 18, 22, 21, 28, 22, 22, 24, 32, 21, 31, 36, 17, 26, 39, 30, 28, 37, 25, 36, 28, 23, 57, 33, 14, 64, 19, 35, 32, 56, 26, 29, 43, 44, 28, 36

Offset: 1

Author

Nathan Fox, Mar 19 2017

Keywords

• nonn

Comments

In calculating terms of this sequence, use the convention that a(n)=0 for n<=0.

Much like the Hofstadter Q-sequence A005185, it is not known if this sequence is defined for all positive n.

Empirically, this sequence appears to grow approximately like n/2 with a lot of noise.

Links

• Nathan Fox, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A005185, A278066, A278067, A278068, A283894, A283895, A283896, A283897.

Programs

Maple

A283893:=proc(n) option remember: if n <= 0 then 0: elif n = 1 then 3: elif n = 2 then 2: else A283893(n-A283893(n-1)) + A283893(n-A283893(n-2)): fi: end: