A278064 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 12; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 12.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 3, 13, 14, 5, 15, 6, 7, 16, 18, 10, 8, 18, 22, 12, 19, 14, 24, 11, 23, 27, 16, 13, 17, 15, 26, 20, 10, 27, 36, 20, 15, 42, 14, 31, 21, 34, 28, 15, 23, 50, 14, 31, 54, 24, 19, 23, 42, 32, 31, 34, 51, 14, 36, 61, 29, 17, 77

Offset: 1

Author

Nathan Fox, Nov 10 2016

Keywords

• nonn
• fini
• full

Comments

Similar to Hofstadter's Q-sequence A005185 but with different starting values.

This sequence has exactly 69 terms, since a(69)=77 and computing a(70) would refer to a(-7).

Links

• Nathan Fox, Table of n, a(n) for n = 1..69
• Nathan Fox, Hofstadter-like Sequences over Nonstandard Integers, Talk given at the Rutgers Experimental Mathematics Seminar, November 10 2016.

Crossrefs

Cf. A005185, A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278065.

Programs

Mathematica

a[n_] := a[n] = If[0 < n < 13, n, a[n-a[n-1]] + a[n-a[n-2]]];
Array[a, 69] (* Paolo Xausa, May 30 2024 *)