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A023995 Number of sets S = {a_1, a_2, ..., a_k}, with 1 < a_i < a_j <= n such that no a_j divides the product of all the others. 3
1, 2, 4, 6, 12, 16, 32, 44, 64, 86, 172, 204, 408, 544, 660, 860, 1720, 2080, 4160, 4800, 5792, 7784, 15568, 17440, 23648, 31616, 40976, 46584, 93168, 102768, 205536, 261600, 316160, 426304, 479616, 524112, 1048224, 1407856, 1699568, 1848384, 3696768, 4049376, 8098752, 9292544 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..44.

Sean A. Irvine, Java program (github)

EXAMPLE

f(4)=6: {}, {2}, {3}, {4}, {2,3}, {3,4}.

CROSSREFS

Cf. A038199.

Sequence in context: A233968 A120453 A326438 * A018189 A239954 A296505

Adjacent sequences:  A023992 A023993 A023994 * A023996 A023997 A023998

KEYWORD

nonn

AUTHOR

Lionel Levine (levine(AT)ultranet.com)

EXTENSIONS

More terms from Sean A. Irvine, Jun 17 2019

STATUS

approved

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Last modified July 17 21:24 EDT 2019. Contains 325109 sequences. (Running on oeis4.)