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A169741
a(n) = smallest k such that A109671(k)=n, or -1 if n does not appear in A109671.
2
1, 3, 7, 39, 17, 15, 169, 33, 31, 135, 313, 231, 337, 1257, 113, 1341, 65, 63, 1043, 1077, 937, 4137, 625, 225, 673, 129, 127, 519, 2057, 903, 2099, 2157, 1849, 2493, 2167, 999, 1081, 2685, 1873, 8277, 1249, 7401, 1343, 8289, 497, 8349, 1079, 5373, 4139, 16827
OFFSET
1,2
MAPLE
# Define A109671:
f:=proc(n) option remember; local t1;
if n = 1 then RETURN(1);
elif n mod 2 = 0 then RETURN(f(n/2));
else t1:= f(n-2)-f((n-1)/2);
if t1 > 0 then RETURN(t1) else RETURN(f(n-2)+f((n-1)/2)); fi; fi; end;
# Compute A169741:
M:=50000: M2:=100;
b1:=[seq(f(n), n=1..M)]: b2:=array(1..M);
for n from 1 to M do b2[n]:=-1; od:
for n from 1 to M do i:=b1[n]; if b2[i]<0 then b2[i]:=n; fi; od:
[seq(b2[i], i=1..M2)];
CROSSREFS
Sequence in context: A258840 A209029 A373774 * A335812 A282427 A192198
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, May 02 2010
STATUS
approved