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 A104308 Number of perfect rulers of length n having the least possible largest difference between any adjacent marks that can occur amongst all perfect rulers of this length. 1
 1, 1, 1, 2, 1, 1, 1, 2, 1, 7, 3, 1, 1, 3, 1, 3, 1, 1, 12, 3, 1, 1, 1, 4, 1, 6, 1, 1, 1, 22, 7, 1, 3, 1, 1, 1, 1, 15, 3, 1, 1, 1, 1, 14, 3, 1, 1, 1, 1, 1, 3, 1, 1, 3, 1, 1, 1, 2, 1, 13, 3, 1, 1, 1, 3, 1, 2, 1, 1, 1, 1, 7, 3, 10, 4, 2, 3, 1, 1, 7, 3, 26, 10, 10, 2, 1, 3, 1, 1, 1, 26, 10, 26, 2, 4, 8, 3, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS For nomenclature related to perfect and optimal rulers see Peter Luschny's "Perfect Rulers" web pages. LINKS Peter Luschny, Perfect and Optimal Rulers. A short introduction. EXAMPLE a(11)=3 because 3 of the A103300(11)/2=15 perfect rulers of length 11 can be constructed using the shortest possible maximum segment length A104307(11)=3: [0,1,2,5,8,11], [0,1,4,6,9,11], [0,1,4,7,9,11], not counting their mirror images. CROSSREFS Cf. A104307 size of minimally required longest segment, A103294 definitions related to complete rulers. Sequence in context: A009191 A114717 A080388 * A175456 A122377 A169758 Adjacent sequences:  A104305 A104306 A104307 * A104309 A104310 A104311 KEYWORD nonn AUTHOR Hugo Pfoertner, Mar 01 2005 STATUS approved

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