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A070034 Numbers n such that n! reduced modulo 2^n is also a power of 2. 3
1, 2, 4, 6, 8, 16, 19, 20, 21, 27, 32, 35, 36, 39, 40, 42, 44, 52, 64, 67, 68, 72, 73, 79, 80, 88, 92, 101, 104, 109, 116, 128, 131, 132, 136, 137, 141, 144, 145, 146, 150, 159, 160, 176, 177, 185, 188, 202, 204, 208, 209, 233, 244, 256, 259, 260, 264, 265 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

T. D. Noe, Table of n, a(n) for n = 1..800

FORMULA

Mod[a(n)!, 2^a(n)] = A068496(n) = 2^w for some integer w.

EXAMPLE

Not rarely,consecutive integers are in the sequence like {19,20,21}, providing residues {65536,262144,262144}.

MATHEMATICA

t = {}; Do[s=Mod[n!, 2^n]; If[IntegerQ[Log[2, s]], AppendTo[t, n]], {n, 300}]; t

CROSSREFS

Cf. A000142, A000079, A068496.

Sequence in context: A160560 A332291 A093109 * A329798 A064408 A316225

Adjacent sequences:  A070031 A070032 A070033 * A070035 A070036 A070037

KEYWORD

nonn

AUTHOR

Labos Elemer, Apr 17 2002

STATUS

approved

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Last modified April 9 06:59 EDT 2020. Contains 333344 sequences. (Running on oeis4.)