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A342642
Numbers k such that A342640(k) = 0.
4
0, 4, 8, 16, 20, 24, 32, 36, 40, 48, 64, 68, 72, 80, 84, 88, 96, 100, 104, 112, 128, 132, 136, 144, 148, 152, 160, 164, 168, 176, 192, 196, 200, 208, 216, 224, 228, 256, 260, 264, 272, 276, 280, 288, 292, 296, 304, 320, 324, 328, 336, 340, 344, 352, 356, 360
OFFSET
1,2
COMMENTS
For any m >= 0:
- let s(m) be the unique finite set of nonnegative integers such that m = Sum_{e in s(m)} 2^e,
- this sequence contains the numbers k such that every nonnegative integer is the sum of two nonnegative integers not in s(k).
All terms are even.
LINKS
EXAMPLE
The first terms, alongside the corresponding sets, are:
n a(n) s(a(n))
-- ---- ---------
1 0 {}
2 4 {2}
3 8 {3}
4 16 {4}
5 20 {2, 4}
6 24 {3, 4}
7 32 {5}
8 36 {2, 5}
9 40 {3, 5}
10 48 {4, 5}
11 64 {6}
12 68 {2, 6}
13 72 {3, 6}
14 80 {4, 6}
15 84 {2, 4, 6}
PROG
(PARI) is(n) = { my (v=0); for (x=0, 2*#binary(n), my (f=0); for (y=0, x, if (!bittest(n, y) && !bittest(n, x-y), f=1; break)); if (!f, v+=2^x)); return (v==0) }
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Mar 17 2021
STATUS
approved