A128092 - OEIS

%I #22 Aug 24 2023 12:06:14

%S 2,4,6,16,30,60,126,256,504,1020,2046,4092,8190,16380,32760,65536,

%T 131070,262134,524286,1048560,2097144,4194300,8388606,16777200,

%U 33554425,67108860,134217702,268435440,536870910,1073741820,2147483646

%N a(n) = largest multiple of n which is <= 2^n.

%F a(n) = n*floor(2^n/n) = n*A000799(n).

%F a(n) = 2^n - (2^n mod n). - _Chai Wah Wu_, Aug 24 2023

%p a:=n->n*floor(2^n/n): seq(a(n),n=1..37); # _Emeric Deutsch_, Feb 16 2007

%t f[n_] := n*Floor[2^n/n];Array[f, 33] (* _Ray Chandler_, Feb 19 2007 *)

%o (Python)

%o def A128092(n): return (m:=1<<n)-(m%n) # _Chai Wah Wu_, Aug 24 2023

%Y Cf. A128093, A000799.

%Y Cf. A000079, A015910.

%K nonn

%O 1,1

%A _Leroy Quet_, Feb 14 2007

%E Extended by _Emeric Deutsch_ and _Ray Chandler_, Feb 19 2007