A282167 a(n) is the minimal sum 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, 3, 6, 7, 11, 13, 17, 19, 25, 27

Offset

1,2

Comments

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).

Links

Table of n, a(n) for n=1..10.

Example

  a(1)  = 1  via [1];
  a(2)  = 3  via [1,2];
  a(3)  = 6  via [1,2,3];
  a(4)  = 7  via [1,2,3,1];
  a(5)  = 11 via [1,2,3,1,4];
  a(6)  = 13 via [1,2,3,1,4,2];
  a(7)  = 17 via [1,2,3,1,4,5,1];
  a(8)  = 19 via [1,2,3,1,4,2,5,1];
  a(9)  = 25 via [1,2,3,1,4,2,5,1,6];
  a(10) = 27 via [1,2,3,1,4,2,5,1,6,2].

Crossrefs

Cf. A259280, A282166, A282168.

Sequence in context: A237883 A153033 A353240 * A076644 A214961 A189626

Adjacent sequences: A282164 A282165 A282166 * A282168 A282169 A282170

Keyword

nonn,more

Author

Peter Kagey, Feb 07 2017

Status

approved