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

1,2

Links

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

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: A173561 A258840 A209029 * A335812 A282427 A192198

Adjacent sequences: A169738 A169739 A169740 * A169742 A169743 A169744

Keyword

nonn

Author

N. J. A. Sloane, May 02 2010

Status

approved