login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A088813
Number of subsets of {1, ..., n} that are double-free or sum-free.
3
1, 2, 4, 7, 14, 26, 43, 79, 137, 246, 398, 733, 1237, 2314, 3586, 6730, 11051, 21096, 31985, 61654, 102730, 199555, 301062, 589746, 942876, 1858881, 2793703, 5524251, 9193512, 18256867, 27396918, 54517922, 88020937, 175434632, 263194662, 525173052
OFFSET
0,2
LINKS
Fausto A. C. Cariboni, Table of n, a(n) for n = 0..75
Eric Weisstein's World of Mathematics, Double-Free Set
Eric Weisstein's World of Mathematics, Sum-Free Set
FORMULA
a(n) = 2^n - A088812(n) = A050291(n)+A085489(n)-A007865(n).
CROSSREFS
Sequence in context: A065455 A220842 A026010 * A347780 A351013 A097596
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Oct 19 2003
EXTENSIONS
Terms a(28) and beyond from Fausto A. C. Cariboni, Sep 29 2020
STATUS
approved