A278057 - OEIS

A278057

Relative of Hofstadter Q-sequence: a(n) = n for 1 <= n <= 5; a(n) = a(n-a(n-1)) + a(n-a(n-2)) for n > 5.

1, 2, 3, 4, 5, 3, 6, 7, 5, 8, 6, 7, 9, 11, 7, 10, 14, 11, 12, 12, 10, 15, 16, 12, 14, 18, 14, 19, 15, 13, 21, 18, 14, 22, 19, 25, 18, 21, 21, 24, 26, 21, 29, 23, 25, 26, 25, 31, 23, 26, 33, 30, 28, 30, 28, 37, 27, 31, 37, 31, 25, 39

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

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.

MATHEMATICA

a[n_] := a[n] = If[0 < n < 6, n, a[n-a[n-1]] + a[n-a[n-2]]];

Array[a, 100] (* Paolo Xausa, May 29 2024 *)

CROSSREFS

Cf. A005185, A278056, A278058, A278059, A278060, A278061, A278062, A278063, A278064, A278065.

Sequence in context: A212644 A351285 A341673 * A366876 A330750 A346099

Adjacent sequences: A278054 A278055 A278056 * A278058 A278059 A278060

KEYWORD

nonn

AUTHOR

Nathan Fox, Nov 10 2016

STATUS

approved