A278067 Relative of Hofstadter Q-sequence: a(1) = 37, a(2) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 2, 37, 39, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 2, 76, 39

Offset: 1

Author

Nathan Fox, Nov 13 2016

Keywords

• nonn
• fini
• full

Comments

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

This sequence has exactly 3850 terms, since a(3850)=0 and computing a(3851) would refer to itself.

Superficially, this sequence behaves similarly to A278066. But, that sequence is infinite, but this sequence dies.

Links

• Nathan Fox, Table of n, a(n) for n = 1..3850
• Nathan Fox, Hofstadter-like Sequences over Nonstandard Integers", Talk given at the Rutgers Experimental Mathematics Seminar, November 10 2016.

Crossrefs

Cf. A005185, A278066, A278068.

Programs

Mathematica

a[1] = 37; 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 30 2024 *)