A278059 Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 7; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 7.

1, 2, 3, 4, 5, 6, 7, 3, 8, 9, 5, 10, 6, 7, 11, 13, 10, 8, 13, 17, 7, 16, 20, 7, 13, 19, 10, 16, 19, 12, 23, 25, 12, 24, 25, 15, 26, 30, 14, 28, 16, 26, 20, 15, 25, 30, 26, 24, 33, 29, 24, 36, 29, 21, 43, 31, 26, 35, 19, 29, 51, 17, 40, 33, 38, 28

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

Programs

Mathematica

a[n_] := a[n] = If[0 < n < 8, n, a[n-a[n-1]] + a[n-a[n-2]]];
Array[a, 100] (* Paolo Xausa, May 29 2024 *)