A107041 First differences of indices of squarefree Pell numbers.

1, 1, 2, 1, 3, 1, 1, 2, 4, 1, 1, 3, 1, 2, 1, 1, 2, 2, 2, 1, 3, 1, 1, 2, 2, 3, 1, 3, 1, 2, 1, 1, 2, 1, 1, 2, 1, 3, 1, 1, 2, 2, 2, 1, 4, 1, 2, 1, 1, 2, 1, 1, 2, 4, 1, 1, 2, 2, 2, 1, 1, 3, 1, 2, 1, 1, 2, 1, 1, 2, 1, 3, 1, 1, 2, 2, 2, 1, 1, 3, 3, 1, 1, 2, 1, 1, 3

Offset

1,3

Links

Amiram Eldar, Table of n, a(n) for n = 1..373

Formula

a(n) = A107040(n+1)-A107040(n). - R. J. Mathar, Jan 04 2017

Mathematica

Rest[Differences[Flatten[Position[LinearRecurrence[{2, 1}, {1, 2}, 100], _?SquareFreeQ]]]] (* Harvey P. Dale, May 30 2019 *)

Crossrefs

Cf. A000129, A005117, A107038, A107039, A107040.

Sequence in context: A188804 A122580 A265332 * A389901 A336812 A281426

Adjacent sequences: A107038 A107039 A107040 * A107042 A107043 A107044

Keyword

nonn

Author

Paul Barry, May 09 2005

Extensions

More terms from Amiram Eldar, Feb 25 2024

Status

approved