\\ Kolakoski's sequence
k = vector(11 000)
k[1] = 1
k[2] = 2
u = 0
for (r=1, oo, for (i=1, k[r], k[u++] = 2-(r%2); if (u==#k, break (2))))

\\ replace runs of k t's by t k's
T(s) = my (z=[], t=-oo, k=0); for (i=1, #s, if (t==s[i], k++, if (k, z=concat(z, vector(t, j, k))); [t,k]=[s[i],1])); z

\\ A306366
Tk = T(k)
for (n=1, min(10 000, #Tk), print (n " " Tk[n]))

quit