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A162213 a(n) = the smallest positive multiple of n with exactly n digits when written in binary. 3
1, 2, 6, 8, 20, 36, 70, 128, 261, 520, 1034, 2052, 4108, 8204, 16395, 32768, 65552, 131076, 262162, 524300, 1048593, 2097172, 4194326, 8388624, 16777225, 33554456, 67108878, 134217748, 268435484, 536870940, 1073741854, 2147483648 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..1000

FORMULA

a(n) = n * ceiling(2^(n-1)/n). - Alois P. Heinz, Jul 11 2009

MAPLE

a := proc (n) local k: for k while nops(convert(k*n, base, 2)) <> n do end do; k*n end proc: seq(a(n), n = 1 .. 24); # Emeric Deutsch, Jul 10 2009

a:= n-> n*ceil(2^(n-1)/n): seq(a(n), n=1..40); # Alois P. Heinz, Jul 11 2009

MATHEMATICA

Array[# Ceiling[2^(# - 1)/#] &, 32] (* Michael De Vlieger, Nov 04 2017 *)

CROSSREFS

Cf. A162214, A053041.

Sequence in context: A143481 A093968 A064713 * A100358 A134136 A185165

Adjacent sequences:  A162210 A162211 A162212 * A162214 A162215 A162216

KEYWORD

base,nonn,easy

AUTHOR

Leroy Quet, Jun 28 2009

EXTENSIONS

More terms from Emeric Deutsch and Alois P. Heinz, Jul 11 2009

STATUS

approved

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Last modified August 12 12:15 EDT 2020. Contains 336439 sequences. (Running on oeis4.)