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A123298
Number of incongruent restricted disjoint covering systems (IRDCS) of length n.
0
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 0, 0, 4, 6, 18, 14, 26, 84, 88, 46, 176, 380, 812, 844, 1770, 2164, 5554, 9244, 25384, 62092, 68176, 85762, 304892, 855072, 1229050, 1805096
OFFSET
1,11
COMMENTS
An IRDCS of length n is a sequence of n integers s(1),...,s(n) with the property that if s(i)=m for some m then the other terms of the sequence with value m are precisely s(i+k*m) for all k such that i+k*m is in [1,n] and further such that any integer appearing in the sequence appears at least twice. For example, the two IRDCS of length n are 6,9,3,4,5,3,6,4,3,5,9 and its reverse.
REFERENCES
Gerry Myerson, Jacky Poon and Jamie Simpson, Incongruent restricted disjoint covering systems, preprint.
CROSSREFS
Sequence in context: A213902 A170770 A107499 * A189877 A189868 A336104
KEYWORD
nice,nonn
AUTHOR
Jamie Simpson, Jun 25 2007, corrected Sep 11 2007
STATUS
approved