

A046702


a(n)=a(na(n1))+a(n1a(n2))+a(n2a(n3)), 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
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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 metaFibonacci sequences." SIAM Journal on Discrete Mathematics 18.4 (2005): 794824. 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 Hofstadtertype 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(nisa(ni1)), i=0..k1);
fi; end;
t1:=[seq(a(n), n=1..100)];


MATHEMATICA

a[n_] := a[n] = a[na[n1]] + a[n1a[n2]] + a[n2a[n3]]; a[1] = a[2] = a[3] = 1; Array[a, 80] (* JeanFrançois 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



