A283889 Relative of Hofstadter Q-sequence: a(n) = max(0, n+10000) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) + a(n-a(n-4)) for n > 0.

10, 10001, 10002, 10003, 10004, 14, 10005, 10006, 10007, 10008, 18, 10009, 10010, 10011, 10012, 22, 10013, 10014, 10015, 10016, 26, 10017, 10018, 10019, 10020, 30, 10021, 10022, 10023, 10024, 34, 10025, 10026, 10027, 37, 10029, 10029, 39

Offset

1,1

Comments

Sequences like this are more naturally considered with the first nonzero term in position 1. But this sequence would then match A000027 for its first 10000 terms.

This sequence has some stretches where it is quasilinear, but it appears to be ultimately chaotic.

Links

Nathan Fox, Table of n, a(n) for n = 1..50000

Maple

A283889:=proc(n) option remember: if n <= 0 then max(0, n+10000): else A283889(n-A283889(n-1)) + A283889(n-A283889(n-2)) + A283889(n-A283889(n-3)) + A283889(n-A283889(n-4)): fi: end:

Crossrefs

Cf. A005185, A283890, A283891, A283892.

Sequence in context: A013746 A076782 A213653 * A283890 A139109 A317959

Adjacent sequences: A283886 A283887 A283888 * A283890 A283891 A283892

Keyword

nonn,look

Author

Nathan Fox, Mar 19 2017

Status

approved