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A069120 Integers of the form k!*sum(i=1..k, 1/(i*2^i) ). 2
4, 3489, 906408439650, 17919252390718041882750, 5699637429226533498825333877162500, 179263970680739996376691111034230475370480684738369155859375 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10

EXAMPLE

4 is in the sequence because for k = 3, 3!*(1/1/2^1 + 1/2/2^2 + 1/3/2^3) = 4 is an integer. - Robert Israel, May 18 2014

MAPLE

select(type, [seq](k!*add(1/i/2^i, i=1..k), k=1..100), integer); # Robert Israel, May 18 2014

CROSSREFS

Cf. A069119.

Sequence in context: A247154 A134908 A114498 * A221191 A110104 A024061

Adjacent sequences:  A069117 A069118 A069119 * A069121 A069122 A069123

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 07 2002

STATUS

approved

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Last modified September 23 07:59 EDT 2021. Contains 347609 sequences. (Running on oeis4.)