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A373408
Minimum of the n-th maximal antirun of squarefree numbers differing by more than one.
11
1, 2, 3, 6, 7, 11, 14, 15, 22, 23, 30, 31, 34, 35, 38, 39, 42, 43, 47, 58, 59, 62, 66, 67, 70, 71, 74, 78, 79, 83, 86, 87, 94, 95, 102, 103, 106, 107, 110, 111, 114, 115, 119, 123, 130, 131, 134, 138, 139, 142, 143, 146, 155, 158, 159, 166, 167, 174, 178, 179
OFFSET
1,2
COMMENTS
The maximum is given by A007674.
An antirun of a sequence (in this case A005117) is an interval of positions at which consecutive terms differ by more than one.
Consists of 1 and all squarefree numbers n such that n - 1 is also squarefree.
FORMULA
a(1) = 1; a(n>1) = A007674(n-1) + 1.
EXAMPLE
Row-minima of:
1
2
3 5
6
7 10
11 13
14
15 17 19 21
22
23 26 29
30
31 33
34
35 37
38
39 41
42
43 46
47 51 53 55 57
MATHEMATICA
First/@Split[Select[Range[100], SquareFreeQ], #1+1!=#2&]//Most
CROSSREFS
Functional neighbors: A005381, A006512, A007674, A072284, A373127, A373410, A373411.
A005117 lists the squarefree numbers, first differences A076259.
A013929 lists the nonsquarefree numbers, first differences A078147.
Sequence in context: A056956 A171033 A269983 * A323066 A002256 A230584
KEYWORD
nonn
AUTHOR
Gus Wiseman, Jun 05 2024
STATUS
approved