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

Author

Paul Barry, May 09 2005

Keywords

• nonn

Links

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

Crossrefs

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

Programs

Mathematica

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

Formula

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

Extensions

More terms from Amiram Eldar, Feb 25 2024