A278068 Relative of Hofstadter Q-sequence: a(1) = 57, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 2, 57, 59, 2, 116, 2, 116, 2, 116, 2, 116, 2, 116, 2, 116, 2, 116

Offset: 1

Author

Nathan Fox, Nov 13 2016

Keywords

• nonn

Comments

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

This sequence is eventually, beginning with a(3128), quasilinear with quasiperiod 1402.

Links

• Nathan Fox, Table of n, a(n) for n = 1..10000
• Nathan Fox, Hofstadter-like Sequences over Nonstandard Integers", Talk given at the Rutgers Experimental Mathematics Seminar, November 10 2016.
• Nathan Fox, Formula for a(n)

Crossrefs

Cf. A005185, A275163, A278066, A278067.

Programs

Mathematica

a[1] = 57; a[2] = 2; a[n_] := a[n] = If[n < 1, 0, a[n-a[n-1]] + a[n-a[n-2]]];
Array[a, 100] (* Paolo Xausa, May 31 2024 *)