A278065 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 13; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 13.

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 3, 14, 15, 5, 16, 6, 7, 17, 19, 10, 8, 19, 23, 12, 20, 14, 25, 11, 24, 28, 16, 13, 17, 15, 27, 20, 20, 34, 27, 24, 12, 45, 17, 27, 28, 36, 22, 28, 33, 26, 37, 30, 29, 32, 37, 31, 24, 40, 46, 15, 52, 35

Offset: 1

Author

Nathan Fox, Nov 10 2016

Keywords

• nonn

Comments

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

Much like the Hofstadter Q-sequence, it is not known if this sequence is defined for all positive n.

a(n) exists for n <= 3*10^7.

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.

Crossrefs

Cf. A005185, A278056, A278057, A278058, A278059, A278060, A278061, A278062, A278063, A278064.

Programs

Mathematica

a[n_] := a[n] = If[0 < n < 14, n, a[n-a[n-1]] + a[n-a[n-2]]];
Array[a, 100] (* Paolo Xausa, May 30 2024 *)