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A213084 Numbers consisting of ones and eights. 3

%I #26 Sep 09 2019 10:58:26

%S 1,8,11,18,81,88,111,118,181,188,811,818,881,888,1111,1118,1181,1188,

%T 1811,1818,1881,1888,8111,8118,8181,8188,8811,8818,8881,8888,11111,

%U 11118,11181,11188,11811,11818,11881,11888,18111,18118,18181,18188,18811,18818

%N Numbers consisting of ones and eights.

%C One and eight begin with vowels. The subsequence of primes begins 11, 181, 811, 1181, 1811, 8111. - _Jonathan Vos Post_, Jun 14 2012

%t Flatten[Table[FromDigits/@Tuples[{1,8},n],{n,5}]] (* _Harvey P. Dale_, Aug 27 2014 *)

%o (Python)

%o res = []

%o i = 0

%o while len (res) < 260:

%o for c in str(i):

%o if c in '18':

%o continue

%o else:

%o break

%o else:

%o res.append(i)

%o i = i + 1

%o print(res)

%o (PARI) is(n) = #setintersect(vecsort(digits(n), , 8), [0, 2, 3, 4, 5, 6, 7, 9])==0 \\ _Felix Fröhlich_, Sep 09 2019

%Y Cf. A020456 (primes in this sequence).

%Y 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 nonn,base,dumb,easy,word

%O 1,2

%A _Jens Ahlström_, Jun 05 2012

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)