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A375305 Terms as well as digits fit the even/even/odd pattern; this is the lexicographically earliest injective sequence with this property.

%I A375305 #15 Aug 12 2024 13:18:11
%S A375305 0,2,1,4,6,3,8,210,21,20,10,23,22,12,25,24,14,27,26,16,29,28,18,41,40,
%T A375305 30,43,42,32,45,44,34,47,46,36,49,48,38,61,60,50,63,62,52,65,64,54,67,
%U A375305 66,56,69,68,58,81,80,70,83,82,72,85,84,74,87,86,76,89,88,78,21001,2010,212,21003,2012,214,21005
%N A375305 Terms as well as digits fit the even/even/odd pattern; this is the lexicographically earliest injective sequence with this property.
%H A375305 Michael S. Branicky, <a href="/A375305/b375305.txt">Table of n, a(n) for n = 1..10000</a>
%e A375305 a(7) = 8, a(8) = 210, a(9) = 21; the three terms follow the even/even/odd pattern and so do their digits: 8/2/1 and 0/2/1.
%o A375305 (Python)
%o A375305 from itertools import count, islice, repeat
%o A375305 def c(s, i):
%o A375305     return all(int(d)%2 == int((i+j)%3 == 2) for j, d in enumerate(s))
%o A375305 def agen(): # generator of terms
%o A375305     seen, s = set(), 0
%o A375305     for n in count(0):
%o A375305         eo = int(n%3 == 2)
%o A375305         an = next(k for k in count(eo, 2) if k not in seen and c(str(k), s))
%o A375305         yield an
%o A375305         seen.add(an)
%o A375305         s += len(str(an))
%o A375305 print(list(islice(agen(), 99))) # _Michael S. Branicky_, Aug 11 2024
%Y A375305 Cf. A217555, A375306.
%K A375305 base,nonn
%O A375305 1,2
%A A375305 _Eric Angelini_, Aug 11 2024