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## Monday, January 14, 2008

### Seven Pairs of Numbers

If two 1s, two 2s and two 3s are arranged like this:

2 3 1 2 1 3

then the two 1s enclose 1 other digit, the two 2s enclose 2 other digits, and the two 3s enclose 3 other digits.

Can you find a similar arrangement using the seven pairs 1, 1, 2, 2,...7, 7?

Theellsburystastelikeellsburys said...

7 2 4 5 2 6 3 4 7 5 3 1 6 1

no strategy, just determination.

ForrestWU said...

It seems that for 1,1,2,2,...,n,n (n>=3) the solutions exist. If we denote a(n) the number of different arrangements, shall we calculate a(n) ?

Anonymous said...

Да уж. По поводу коментариев - навеяла на меня где-то услышанная фраза:
Именно НАША уникальная культура насчитывает более трех миллионов матерных частушек.