A278058 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 6; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 6.

1, 2, 3, 4, 5, 6, 3, 7, 8, 5, 9, 6, 7, 10, 12, 10, 8, 12, 12, 14, 11, 16, 9, 19, 16, 8, 21, 17, 13, 15, 22, 13, 23, 20, 18, 22, 24, 20, 24, 24, 16, 20, 30, 29, 22, 27, 30, 23, 20, 36, 34, 22, 34, 27, 28, 30, 34, 36, 25, 37, 41, 27, 38, 32, 44, 36, 31

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, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Programs

Mathematica

a[n_] := a[n] = If[0 < n < 7, n, a[n-a[n-1]] + a[n-a[n-2]]];
Array[a, 100] (* Paolo Xausa, May 29 2024 *)