Albert
Frank
The following series need very few mathematical knowledge and are
culture free. Some are extremely
difficult. Each answer has to be clearly explained, in English or in French. The
solutions must be send before March 1st 2003, by e-mail (with subject
« International contest 2002 – 2003 ») to albert.frank@skynet.be or by mail:
Albert Frank
13 Clos du Parnasse / box 45
1050 Brussels
BELGIUM
Good luck !
1) 2, 6, 15, ?,
55, ?, 119
2) 4, ?, 5, 2, 6, 10, 3,
7, 6
3) 1, 3, 9, 9, 9, 9, 18, 18,
18, 27, 27, ?, ?
4) 0, 0, 2, 0, 2, 4, 2,
0, ?, ?
5) 6, 3, 20, 7, ?,
117, ?, 114
6) 6, 7, 2, 1, 5,
9, ?, ?, ?
7) ?, -1, -1, -1, 0, 2, 6, 13,
25, ?
8) 2614534, 4?45??
9) 1, 2, 3, 5, 8, 10, ?,
16, 23
10) 1010, 202, 132, 130, 122,
114, 106, ?, 90
11) 4, 9, 7, 13, ?, 16,
19, ?, 16, 13
12) Why are there two * in this
finite sequence?
1, 5, 9, 6, 3, *, 2, 4, *,
7, 8, 9
13) 5, 6, 7, 8, 8, 8,
8, ?, ?
14) 4, 6, 10, ?, 3, 7, 15,
19, 11, ?
15) 6, 14, 6, 5, 40, 90,
104, ?
16) -1, -1, 1, 17, 109,
707, ?
17) 1, 2, 3, 6, ?, 6, 3, 6,
1
18) 0, 1, 2, 3, 1, 1, ?,
3, ?, 9
19) 11, 23, 44, 56, 48,
67, ?
20) 1, 2, 2, 1, 2, 4, 2, 2, 1,
2, ?, 2, 2, 1, 2, 2, 2, ?, 2, 1
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