A350127 a(n) = a(a(n-1)) mod 3 + a(n-2) with a(0) = 0 and a(1) = 1.

0, 1, 1, 2, 2, 3, 4, 5, 4, 7, 6, 8, 7, 10, 7, 12, 8, 13, 9, 14, 10, 14, 11, 16, 13, 17, 14, 18, 14, 19, 16, 21, 18, 21, 20, 22, 22, 24, 23, 25, 25, 27, 25, 29, 26, 31, 26, 33, 26, 35, 27, 35, 28, 37, 28, 39, 29, 40, 30, 41, 30, 42, 31, 42, 32, 42, 33, 42, 34

Offset

0,4

Comments

It appears that lim_{n->infinity} a(n)/n = 0.562...

Are there infinitely many k such that a(k) = a(k+1)?

Conjecture: The density of even terms is 1/2.

Links

Jon Maiga, Table of n, a(n) for n = 0..10000

Mathematica

a[0] = 0;
a[1] = 1;
a[n_] := a[n] = Mod[a[a[n - 1]], 3] + a[n - 2]
Array[a, 100, 0]

Prog

(Python)
a = [0, 1]
[a.append(a[a[n-1]]%3 + a[n-2]) for n in range(2, 69)]
print(a) # Michael S. Branicky, Dec 15 2021

Crossrefs

Cf. A350126.

Sequence in context: A292259 A241397 A331049 * A320159 A342879 A342880

Adjacent sequences: A350124 A350125 A350126 * A350128 A350129 A350130

Keyword

nonn,look

Author

Jon Maiga, Dec 15 2021

Status

approved