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A240827 a(n) = n for 1<=n<=6; thereafter a(n) = a(n-a(n-3))+a(n-a(n-6)). 4
1, 2, 3, 4, 5, 6, 9, 9, 9, 7, 8, 9, 10, 11, 12, 15, 15, 15, 13, 14, 15, 18, 18, 18, 18, 18, 18, 14, 16, 18, 25, 26, 24, 23, 22, 24, 20, 24, 24, 29, 28, 30, 29, 29, 27, 30, 28, 30, 27, 33, 33, 36, 32, 33, 27, 36, 36, 43, 36, 36, 38, 36, 36, 33, 32, 36, 39, 50, 48, 45, 39, 42, 37, 40, 42, 49, 44, 48, 48, 53, 48, 47, 42, 48, 44, 53, 48, 57, 52, 60 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Conjectured to be infinite.

REFERENCES

D. R. Hofstadter, Curious patterns and non-patterns in a family of meta-Fibonacci recursions, Lecture in Doron Zeilberger's Experimental Mathematics Seminar, Rutgers University, April 10 2014.

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..50000

D. R. Hofstadter, Curious patterns and non-patterns in a family of meta-Fibonacci recursions, Lecture in Doron Zeilberger's Experimental Mathematics Seminar, Rutgers University, April 10 2014; Part 1, Part 2.

Index entries for Hofstadter-type sequences

MAPLE

#Q(r, s) with initial values 1, 2, 3, 4, ...

r:=3; s:=6;

a:=proc(n) option remember; global r, s;

if n <= s then n

else

if (a(n-r) <= n) and (a(n-s) <= n) then

a(n-a(n-r))+a(n-a(n-s));

else lprint("died with n =", n); return (-1);

fi;

fi; end;

t2:=[seq(a(n), n=1..100)];

PROG

(MAGMA) I:=[1, 2, 3, 4, 5, 6]; [n le 6 select I[n] else Self(n-Self(n-3))+Self(n-Self(n-6)): n in [1..100]]; // Vincenzo Librandi, Apr 16 2014

CROSSREFS

Cf. A240821.

Sequence in context: A269847 A245705 A075164 * A023841 A245605 A269863

Adjacent sequences:  A240824 A240825 A240826 * A240828 A240829 A240830

KEYWORD

nonn,hear

AUTHOR

N. J. A. Sloane, Apr 15 2014

STATUS

approved

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Last modified October 29 12:00 EDT 2020. Contains 338066 sequences. (Running on oeis4.)