A283897 Relative of Hofstadter Q-sequence: a(-90) = 91, a(-89) = 2; thereafter a(n) = a(n-a(n-1)) + a(n-a(n-2)).

93, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2, 184, 2

Offset: 1

Author

Nathan Fox, Mar 19 2017

Keywords

• nonn
• fini
• full

Comments

In calculating terms of this sequence, use the convention that a(n)=0 for n<=-91.

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then begin with 91 terms consisting entirely of alternating 2 and 91.

This sequence has exactly 375 terms, since a(375)=0 and computing a(376) would refer to itself.

Links

• Nathan Fox, Table of n, a(n) for n = 1..375

Crossrefs

Cf. A005185, A278066, A278067, A278068, A283893, A283894, A283895, A283896.

Programs

Maple

A283897:=proc(n) option remember: if n <= -91 then 0: elif n = -90 then 91: elif n = -89 then 2: else A283897(n-A283897(n-1)) + A283897(n-A283897(n-2)): fi: end: