A128092 a(n) = largest multiple of n which is <= 2^n.

2, 4, 6, 16, 30, 60, 126, 256, 504, 1020, 2046, 4092, 8190, 16380, 32760, 65536, 131070, 262134, 524286, 1048560, 2097144, 4194300, 8388606, 16777200, 33554425, 67108860, 134217702, 268435440, 536870910, 1073741820, 2147483646

Offset

1,1

Links

Table of n, a(n) for n=1..31.

Formula

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

a(n) = 2^n - (2^n mod n). - Chai Wah Wu, Aug 24 2023

Maple

a:=n->n*floor(2^n/n): seq(a(n), n=1..37); # Emeric Deutsch, Feb 16 2007

Mathematica

f[n_] := n*Floor[2^n/n]; Array[f, 33] (* Ray Chandler, Feb 19 2007 *)

Prog

(Python)
def A128092(n): return (m:=1<<n)-(m%n) # Chai Wah Wu, Aug 24 2023

Crossrefs

Cf. A128093, A000799.

Cf. A000079, A015910.

Sequence in context: A045665 A133492 A045663 * A167569 A032503 A050838

Adjacent sequences: A128089 A128090 A128091 * A128093 A128094 A128095

Keyword

nonn

Author

Leroy Quet, Feb 14 2007

Extensions

Extended by Emeric Deutsch and Ray Chandler, Feb 19 2007

Status

approved