A283891 - OEIS

%I #6 Mar 30 2017 21:29:10

%S 28,10001,10002,10003,10004,10005,10006,10007,35,10008,10009,10010,

%T 10011,10012,10013,10014,42,10015,10016,10017,10018,10019,10020,10021,

%U 49,10022,10023,10024,10025,10026,10027,10028,56,10029,10030,10031,10032,10033,10034,10035,63

%N Relative of Hofstadter Q-sequence.

%C This sequence is defined by 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)) + a(n-a(n-5)) + a(n-a(n-6)) + a(n-a(n-7)) for n > 0.

%C 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.

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

%H Nathan Fox, <a href="/A283891/b283891.txt">Table of n, a(n) for n = 1..50000</a>

%p A283891:=proc(n) option remember: if n <= 0 then max(0, n+10000): else A283891(n-A283891(n-1)) + A283891(n-A283891(n-2)) + A283891(n-A283891(n-3)) + A283891(n-A283891(n-4)) + A283891(n-A283891(n-5)) + A283891(n-A283891(n-6)) + A283891(n-A283891(n-7)): fi: end:

%Y Cf. A005185, A283889, A283890, A283892.

%K nonn,look

%O 1,1

%A _Nathan Fox_, Mar 19 2017