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A282170 a(n) is the minimal product of a positive integer sequence of length n with no duplicate substrings (forward or backward) of length greater than 1, and no self-adjacent terms. 1
1, 2, 6, 6, 24, 48, 120, 240, 1440, 2880, 10080 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
EXAMPLE
a(1) = 1 via [1];
a(2) = 2 via [1,2];
a(3) = 6 via [1,2,3];
a(4) = 6 via [1,2,3,1];
a(5) = 24 via [1,2,3,1,4];
a(6) = 48 via [1,2,3,1,4,2];
a(7) = 120 via [1,2,3,1,4,5,1];
a(8) = 240 via [1,2,3,1,4,2,5,1];
a(9) = 1440 via [1,2,3,1,4,2,5,1,6];
a(10) = 2880 via [1,2,3,1,4,2,5,1,6,2];
a(11) = 10080 via [1,2,3,1,4,2,5,1,6,7,1].
Examples:
[1,1] is invalid because 1 is self-adjacent.
[1,2,3,1,2] is invalid because the substring [1,2] appears twice.
[1,2,1] is invalid because the substring [1,2] appears twice (once forward and once backward).
CROSSREFS
Cf. A282167 is the sum analog.
Sequence in context: A325803 A130865 A327630 * A105725 A005226 A087310
KEYWORD
nonn,more
AUTHOR
Peter Kagey, Feb 07 2017
STATUS
approved

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Last modified March 29 08:13 EDT 2024. Contains 371265 sequences. (Running on oeis4.)