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%I #9 Jan 12 2021 21:34:11
%S 1,12,1221,1221121,12211212212,122112122122112112,
%T 1221121221221121122121121221,
%U 1221121221221121122121121221121121221221121,12211212212211211221211212211211212212211212212112112212211212212
%N Successive generations of the Kolakoski sequence A000002.
%o (Python)
%o from itertools import accumulate, groupby, repeat
%o def K(n, _):
%o c, s = "12", ""
%o for i, k in enumerate(str(n)): s += c[i%2]*int(k)
%o return int(s + c[(i+1)%2])
%o def aupton(nn): return list(accumulate(repeat(1, nn+1), K))
%o print(aupton(8)) # _Michael S. Branicky_, Jan 12 2021
%Y Cf. A054348, A054349, A054350, A054352, A042942, A000002.
%Y Word lengths give A054352.
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_, May 07 2000
%E More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 05 2003
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