cp's OEIS Frontend

A266001 Numbers with no 0's in their base 3 and base 4 expansions.

%I A266001 #23 Feb 13 2016 23:02:30
%S A266001 1,2,5,7,13,14,22,23,25,26,41,43,53,121,122,125,149,151,157,158,214,
%T A266001 215,229,230,233,238,239,365,367,373,374,377,445,446,473,475,485,607,
%U A266001 617,619,634,635,637,638,697,698,701,725,727,1366,1367,1373,1375,1429,1430,1445,1447,1453,1454
%N A266001 Numbers with no 0's in their base 3 and base 4 expansions.
%C A266001 Intersection of A023705 and A032924.
%C A266001 1, 7 and 32767 also share this property in base 2.
%H A266001 Chai Wah Wu, <a href="/A266001/b266001.txt">Table of n, a(n) for n = 1..12682</a>
%e A266001 53 is 1222 in base 3 and 311 in base 4; no zeros are shown in either representation and so 53 is a term.
%e A266001 Similarly, 121 is 11111 in base 3 and 1321 in base 4 so it is also a term.
%o A266001 (PARI) isokd(n) = vecmin(digits(n, 3)) && vecmin(digits(n, 4)); \\ _Michel Marcus_, Jan 28 2016
%o A266001 (Python)
%o A266001 from __future__ import division
%o A266001 from gmpy2 import digits
%o A266001 A266001_list = [j for j in (int(format(i,'b'),3)+(3**n-1)//2 for n in range(1,10) for i in range(2**n)) if '0' not in digits(j,4)] # _Chai Wah Wu_, Feb 13 2016
%Y A266001 Cf. A023705, A032924, A262958, A262963.
%K A266001 nonn,base
%O A266001 1,2
%A A266001 _Robin Powell_, Jan 27 2016