A161764 a(n) is the largest multiple of {the number of 1's in the binary representation of n} that is <= n.

1, 2, 2, 4, 4, 6, 6, 8, 8, 10, 9, 12, 12, 12, 12, 16, 16, 18, 18, 20, 21, 21, 20, 24, 24, 24, 24, 27, 28, 28, 30, 32, 32, 34, 33, 36, 36, 36, 36, 40, 39, 42, 40, 42, 44, 44, 45, 48, 48, 48, 48, 51, 52, 52, 55, 54, 56, 56, 55, 60, 60, 60, 60, 64, 64, 66, 66, 68, 69, 69, 68, 72, 72

Offset: 1

Author

Leroy Quet, Jun 18 2009

Keywords

• base
• nonn

Comments

a(n) = n - A199238(n). - Reinhard Zumkeller, Nov 04 2011

Examples

			11 (decimal) in binary is 1011. There are three 1's. Because 9 is the largest multiple of 3 that is <= 11, then a(11) = 9.
		

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000120, A161765.

Programs

Haskell

a161764 n = n - a199238 n  -- Reinhard Zumkeller, Nov 04 2011

Maple

a := proc (n) local n2, n1, j: n2 := convert(n, base, 2): n1 := add(n2[i], i = 1 .. nops(n2)): for j while j*n1 <= n do j*n1 end do end proc: seq(a(n), n = 1 .. 80); # Emeric Deutsch, Jun 26 2009

PARI

a(n)=local(B=binary(n),w=B*vector(#B,x,1)~);n-n%w \\ Hagen von Eitzen, Jun 22 2009

Extensions

Extended by Hagen von Eitzen and Emeric Deutsch, Jun 26 2009