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A046702 a(n)=a(n-a(n-1))+a(n-1-a(n-2))+a(n-2-a(n-3)), n>3. a(1)=a(2)=a(3)=1. 9
1, 1, 1, 3, 3, 3, 5, 5, 7, 5, 7, 7, 9, 9, 9, 11, 11, 13, 11, 15, 13, 17, 13, 17, 15, 19, 17, 19, 17, 21, 19, 23, 19, 23, 21, 25, 23, 25, 25, 27, 27, 27, 29, 29, 31, 29, 33, 31, 35, 31, 37, 33, 39, 33, 41, 35, 43, 35, 43, 37, 45, 39, 45, 39, 47, 41, 49, 41, 49, 43, 51, 45, 51, 45 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

REFERENCES

Sequence proposed by Reg Allenby.

Callaghan, Joseph, John J. Chew III, and Stephen M. Tanny. "On the behavior of a family of meta-Fibonacci sequences." SIAM Journal on Discrete Mathematics 18.4 (2005): 794-824. See T_{0,3} with initial values 1,1,1, as in Fig. 1.6. - N. J. A. Sloane, Apr 16 2014

LINKS

N. J. A. Sloane, Table of n, a(n) for n = 1..20000

Index entries for Hofstadter-type sequences

MAPLE

#T_s, k(n) from Callaghan et al. Eq. (1.6). - From N. J. A. Sloane, Apr 16 2014

s:=0; k:=3;

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

if n <= 2 then 1

elif n = 3 then 1

else

    add(a(n-i-s-a(n-i-1)), i=0..k-1);

fi; end;

t1:=[seq(a(n), n=1..100)];

MATHEMATICA

a[n_] := a[n] = a[n-a[n-1]] + a[n-1-a[n-2]] + a[n-2-a[n-3]]; a[1] = a[2] = a[3] = 1; Array[a, 80] (* Jean-Fran├žois Alcover, Dec 12 2016 *)

CROSSREFS

Cf. A240833, A240834.

Callaghan et al. (2005)'s sequences T_{0,k}(n) for k=1 through 7 are A000012, A046699, A046702, A240835, A241154, A241155, A240830.

Sequence in context: A101435 A077886 A096015 * A226592 A133683 A182998

Adjacent sequences:  A046699 A046700 A046701 * A046703 A046704 A046705

KEYWORD

nonn,look

AUTHOR

R. K. Guy

EXTENSIONS

Corrected and extended by Michael Somos

STATUS

approved

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Last modified August 20 10:41 EDT 2019. Contains 326150 sequences. (Running on oeis4.)