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| | Langford Numbers |
 | | Definition: A (k,n) Langford sequence is a rearrangement of the sequence 1,1,...,1,2,2,...,2,3,3,...,3,...,n,n,...,n (k copies of the integers from 1 to n) such that between each occurrence of the integer i there are i integers. |
 | | In a (2,n) Langford sequence there are 2n positions to be filled. |
 | | Baron, Uber Verallgemeinerungen des Langford'schen Problems; in P. Erdos, A Renyi and V. Sos (ed.), Combinatorial theory and its applications I, p. |
| www.tiac.net /~tiberio/vita/langford.htm (564 words) |
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