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 A135464 Numbers n with property that for each single digit d of the base 3 expansion of n, we can also see the base 3 expansion of d^2 as a substring. Also n may not contain any 0 digits. 2

%I #11 Aug 20 2023 10:51:49

%S 1,11,111,112,211,1111,1112,1121,1122,1211,2111,2112,2211,11111,11112,

%T 11121,11122,11211,11212,11221,11222,12111,12112,12211,21111,21112,

%U 21121,21122,21211,22111,22112,22211,111111,111112,111121

%N Numbers n with property that for each single digit d of the base 3 expansion of n, we can also see the base 3 expansion of d^2 as a substring. Also n may not contain any 0 digits.

%C The base 3 expansion of n may only contain 1's and 2's and if a 2 is present then 11 must also be present. These are the only restrictions.

%H David Applegate, <a href="/A135464/b135464.txt">Table of n, a(n) for n = 1..300</a>

%o (AWK) awk 'function g(s,v,n){if (n==0){if (index(s,"2")==0||index(s,"11")>0)print v;}else{g(s "1",v*3+1,n-1); g(s "2",v*3+2,n-1);}}BEGIN{for (i=1; i<=8; i++)g("",0,i);}' # _David Applegate_

%o (C++) // See the Applegate link in A135463.

%Y Base-3 analog of A134962. Cf. A135465.

%K nonn,base,easy

%O 1,2

%A _David Applegate_ and _N. J. A. Sloane_, Feb 07 2008

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Last modified December 6 09:20 EST 2023. Contains 367600 sequences. (Running on oeis4.)