OFFSET
1,2
LINKS
Ray Chandler, Table of n, a(n) for n = 1..2024
FORMULA
a(n) = n*A102032(n). - Vladeta Jovovic, Sep 17 2008
EXAMPLE
For n = 3, checking: 3*1=3 (11 in binary, two 1's). 3*2=6 (110 in binary, two 1's). 3*3=9 (1001 in binary, two 1's). 3*4=12 (1100 in binary, two 1's). 3*5=15 (1111 in binary, four 1's). 3*6=18 (10010 in binary, two 1's). 3*7=21 (10101 in binary, three 1's). So a(3) = 21.
MAPLE
a:=proc(n) local k: for k while add(convert(k*n, base, 2)[j], j=1..nops(convert(k*n, base, 2))) <> n do end do: k*n end proc: seq(a(n), n=1..16); # Emeric Deutsch, Aug 16 2008
MATHEMATICA
Fold[Append[#1, SelectFirst[Range[2^#2] #2, Function[k, DigitCount[k, 2, 1] == #2]]] &, {1}, Range[2, 20]] (* Michael De Vlieger, Oct 25 2017 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Leroy Quet, Jul 25 2008
EXTENSIONS
More terms from Emeric Deutsch, Aug 16 2008
a(17) to a(27) from Owen Whitby, Oct 22 2008. For n=28,29,30 if a(n) exists it is greater than 20000000n.
a(28)-a(29) from Ray Chandler, Nov 11 2008
STATUS
approved