login
Numbers with a single 1 in their base 5 expansion.
2

%I #12 Apr 02 2014 05:00:52

%S 1,5,7,8,9,11,16,21,25,27,28,29,35,37,38,39,40,42,43,44,45,47,48,49,

%T 51,55,57,58,59,61,66,71,76,80,82,83,84,86,91,96,101,105,107,108,109,

%U 111,116,121,125,127,128,129,135,137,138,139

%N Numbers with a single 1 in their base 5 expansion.

%H Vincenzo Librandi, <a href="/A023726/b023726.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[ Range[ 150 ], (Count[ IntegerDigits[ #, 5 ], 1 ]==1)& ]

%o (PARI) is(n)=my(v=digits(n,5)); sum(i=1,#v,v[i]==1)==1 \\ _Charles R Greathouse IV_, Mar 31 2014

%K nonn,base,easy

%O 1,2

%A _Olivier GĂ©rard_