A169741 a(n) = smallest k such that A109671(k)=n, or -1 if n does not appear in A109671.

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

Author

N. J. A. Sloane, May 02 2010

Keywords

• nonn

Links

• Zak Seidov, Table of n, a(n) for n = 1..2443

Programs

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)];