A283890 Relative of Hofstadter Q-sequence: a(n) = max(0, n+10001) 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, 10002, 10003, 10004, 10005, 14, 10006, 10007, 10008, 10009, 18, 10010, 10011, 10012, 10013, 22, 10014, 10015, 10016, 10017, 26, 10018, 10019, 10020, 10021, 30, 10022, 10023, 10024, 10025, 34, 10026, 10027, 10028, 37, 10030, 10030, 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 10001 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

A283890:=proc(n) option remember: if n <= 0 then max(0, n+10001): else A283890(n-A283890(n-1)) + A283890(n-A283890(n-2)) + A283890(n-A283890(n-3)) + A283890(n-A283890(n-4)): fi: end:

Crossrefs

Cf. A005185, A283889, A283891, A283892.

Sequence in context: A076782 A213653 A283889 * A139109 A317959 A119037

Adjacent sequences: A283887 A283888 A283889 * A283891 A283892 A283893

Keyword

nonn,look

Author

Nathan Fox, Mar 19 2017

Status

approved