A088812 Number of subsets of {1, ..., n} that are neither double-free nor sum-free.

0, 0, 0, 1, 2, 6, 21, 49, 119, 266, 626, 1315, 2859, 5878, 12798, 26038, 54485, 109976, 230159, 462634, 945846, 1897597, 3893242, 7798862, 15834340, 31695551, 64315161, 128693477, 259241944, 518614045, 1046344906, 2092965726, 4206946359, 8414499960

Offset: 0

Author

Reinhard Zumkeller, Oct 19 2003

Keywords

• nonn

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
• Reinhard Zumkeller, Illustration of initial terms

Formula

a(n) = 2^n - A088813(n) = A088808(n)-A088811(n) = A088809(n)-A088810(n).

Extensions

Terms a(28) and beyond from Fausto A. C. Cariboni, Sep 29 2020