(phixonline)-->
sequence sb = {1,1}
integer c = 2
function stern_brocot(integer n)
while length(sb)<n do
sb &= sb[c]+sb[c-1] & sb[c]
c += 1
end while
return sb[1..n]
end function
sequence s = stern_brocot(15)
puts(1,"first 15:")
?s
integer n = 16, k
sequence idx = tagset(10)
for i=1 to length(idx) do
while 1 do
k = find(idx[i],s)
if k!=0 then exit end if
n *= 2
s = stern_brocot(n)
end while
idx[i] = k
end for
puts(1,"indexes of 1..10:")
?idx
puts(1,"index of 100:")
while 1 do
k = find(100,s)
if k!=0 then exit end if
n *= 2
s = stern_brocot(n)
end while
?k
s = stern_brocot(1000)
integer maxgcd = 1
for i=1 to 999 do
maxgcd = max(gcd(s[i],s[i+1]),maxgcd)
end for
printf(1,"max gcd:%d\n",{maxgcd})