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A213084 Numbers consisting of ones and eights.

%I A213084 #33 Jun 28 2025 20:22:16
%S A213084 1,8,11,18,81,88,111,118,181,188,811,818,881,888,1111,1118,1181,1188,
%T A213084 1811,1818,1881,1888,8111,8118,8181,8188,8811,8818,8881,8888,11111,
%U A213084 11118,11181,11188,11811,11818,11881,11888,18111,18118,18181,18188,18811,18818
%N A213084 Numbers consisting of ones and eights.
%C A213084 One and eight begin with vowels. The subsequence of primes begins 11, 181, 811, 1181, 1811, 8111. - _Jonathan Vos Post_, Jun 14 2012
%H A213084 Alois P. Heinz, <a href="/A213084/b213084.txt">Table of n, a(n) for n = 1..16382</a>
%t A213084 Flatten[Table[FromDigits/@Tuples[{1,8},n],{n,5}]] (* _Harvey P. Dale_, Aug 27 2014 *)
%o A213084 (Python)
%o A213084 res = []
%o A213084 i = 0
%o A213084 while len (res) < 260:
%o A213084     for c in str(i):
%o A213084         if c in '18':
%o A213084             continue
%o A213084         else:
%o A213084             break
%o A213084     else:
%o A213084         res.append(i)
%o A213084     i = i + 1
%o A213084 print(res)
%o A213084 (Python)
%o A213084 def a(n): return int(bin(n+1)[3:].replace('1', '8').replace('0', '1'))
%o A213084 print([a(n) for n in range(1, 45)]) # _Michael S. Branicky_, Jun 26 2025
%o A213084 (PARI) is(n) = #setintersect(vecsort(digits(n), , 8), [0, 2, 3, 4, 5, 6, 7, 9])==0 \\ _Felix Fröhlich_, Sep 09 2019
%Y A213084 Cf. A020456 (primes in this sequence).
%Y A213084 Cf. numbers consisting of 1s and ks: A007088 (k=0), A007931 (k=2), A032917 (k=3), A032822 (k=4), A276037 (k=5), A284293 (k=6), A276039 (k=7), A284294 (k=9).
%K A213084 nonn,base,easy,word
%O A213084 1,2
%A A213084 _Jens Ahlström_, Jun 05 2012