A282164 a(n) is the minimal product of a positive integer sequence of length n with no duplicate substrings of length greater than 1.

1, 1, 2, 2, 4, 6, 12, 24, 48, 120, 240, 720, 1440, 4320, 8640, 25920, 60480, 181440, 483840, 1451520, 3870720, 11612160, 34836480, 104509440, 348364800, 1045094400, 3483648000, 10450944000, 38320128000, 114960384000, 459841536000, 1379524608000, 5518098432000, 16554295296000

Offset

1,3

Comments

a(n) = sqrt(A282165(n-1)) if A282165(n-1) is square.

Links

Peter Kagey, Table of n, a(n) for n = 1..100

Example

  a(1)  = 1   via [1];
  a(2)  = 1   via [1,1];
  a(3)  = 2   via [1,1,2];
  a(4)  = 2   via [1,1,2,1];
  a(5)  = 4   via [1,1,2,2,1];
  a(6)  = 6   via [1,1,2,1,3,1];
  a(7)  = 12  via [1,1,2,2,1,3,1];
  a(8)  = 24  via [1,1,2,1,3,1,4,1];
  a(9)  = 48  via [1,1,2,2,1,3,1,4,1];
  a(10) = 120 via [1,1,2,1,3,1,4,1,5,1].

Crossrefs

Product analog of A259280.

Sequence in context: A128209 A274935 A188538 * A268175 A363578 A209025

Adjacent sequences: A282161 A282162 A282163 * A282165 A282166 A282167

Keyword

nonn

Author

Peter Kagey, Braxton Carrigan, Feb 07 2017

Status

approved