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A088810 Number of subsets of {1, ..., n} that are double-free but not sum-free. 2
0, 0, 0, 0, 1, 4, 6, 18, 35, 84, 137, 323, 591, 1313, 2033, 4360, 7406, 15581, 23682, 49184, 84017, 171744, 259818, 528784, 853143, 1727011, 2601181, 5243126 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,6

COMMENTS

a(n) = A050291(n) - A007865(n) = A088809(n) - A088812(n).

LINKS

Table of n, a(n) for n=0..27.

Eric Weisstein's World of Mathematics, Double-Free Set

Eric Weisstein's World of Mathematics, Sum-Free Set

Reinhard Zumkeller, Illustration of initial terms

CROSSREFS

Sequence in context: A156096 A281861 A218898 * A005199 A107390 A051253

Adjacent sequences:  A088807 A088808 A088809 * A088811 A088812 A088813

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Oct 19 2003

STATUS

approved

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Last modified February 17 17:27 EST 2019. Contains 320222 sequences. (Running on oeis4.)