A375738 Minimum of the n-th maximal anti-run of adjacent (increasing by more than one at a time) non-perfect-powers.

2, 3, 6, 7, 11, 12, 13, 14, 15, 18, 19, 20, 21, 22, 23, 24, 29, 30, 31, 34, 35, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 83, 84, 85, 86, 87, 88

Offset

1,1

Comments

Non-perfect-powers (A007916) are numbers with no proper integer roots.

An anti-run of a sequence is an interval of positions at which consecutive terms differ by more than one.

Links

Table of n, a(n) for n=1..66.

Example

The initial anti-runs are the following, whose minima are a(n):
  (2)
  (3,5)
  (6)
  (7,10)
  (11)
  (12)
  (13)
  (14)
  (15,17)
  (18)
  (19)
  (20)
  (21)
  (22)
  (23)
  (24,26,28)

Mathematica

radQ[n_]:=n>1&&GCD@@Last/@FactorInteger[n]==1;
Min/@Split[Select[Range[100], radQ], #1+1!=#2&]//Most

Crossrefs

For composite numbers we have A005381, runs A008864 (except first term).

For prime-powers we have A120430, runs A373673 (except first term).

For squarefree numbers we have A373408, runs A072284.

For nonsquarefree numbers we have A373410, runs A053806.

For non-prime-powers we have A373575, runs A373676.

For anti-runs of non-perfect-powers:

- length: A375736

- first: A375738 (this)

- last: A375739

- sum: A375737

For runs of non-perfect-powers:

- length: A375702

- first: A375703

- last: A375704

- sum: A375705

A001597 lists perfect-powers, differences A053289.

A007916 lists non-perfect-powers, differences A375706.

Cf. A007674, A045542, A046933, A061399, A216765, A251092, A373403, A373679, A375708, A375714.

Sequence in context: A362286 A050031 A003421 * A253239 A226384 A298947

Adjacent sequences: A375735 A375736 A375737 * A375739 A375740 A375741

Keyword

nonn

Author

Gus Wiseman, Sep 10 2024

Status

approved