|
| |
|
|
A143146
|
|
a(n) = the smallest positive multiple of n that has the same number of 0's as 1's in its binary representation.
|
|
1
| |
|
|
2, 2, 9, 12, 10, 12, 35, 56, 9, 10, 44, 12, 52, 42, 135, 240, 153, 180, 38, 180, 42, 44, 184, 216, 50, 52, 135, 56, 232, 150, 527, 992, 165, 170, 35, 180, 37, 38, 156, 240, 41, 42, 172, 44, 135, 184, 141, 240, 49, 50, 153, 52, 212, 216, 165, 56, 228, 232, 177, 180
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
EXAMPLE
| For n = 7, checking: 7*1 = 7 = 111 in binary; 7*2 = 14 = 1110 in binary; 7*3 = 21 = 10101 in binary; 7*4 = 28 = 11100. All of these have two many 1's in binary. But 7*5 = 35 = 100011 in binary, which has both three 0's and three 1's. So a(7) = 35.
|
|
|
MAPLE
| a:=proc(n) local b, k: b:=proc(m) convert(m, base, 2) end proc: for k while add(b(k*n)[j], j=1..nops(b(k*n))) <> nops(b(k*n))-add(b(k*n)[j], j=1..nops(b(k*n))) do end do: k*n end proc: seq(a(n), n=1..60); [From Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008]
|
|
|
CROSSREFS
| Cf. A031443, A143147.
Sequence in context: A154100 A002880 A066324 * A185755 A039796 A007024
Adjacent sequences: A143143 A143144 A143145 * A143147 A143148 A143149
|
|
|
KEYWORD
| base,nonn
|
|
|
AUTHOR
| Leroy Quet Jul 27 2008
|
|
|
EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Aug 16 2008
|
| |
|
|
