A175408 a(n) + a(n - 1) is alternatively a cube or a square.

1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3, 5, 4, 4, 5, 3, 1, 7, 2, 6, 3

Offset

1,2

Comments

a(1)=1, then a(2n) = (the least cube > a(2n-1)) - a(2n-1), and a(2n+1) = (the least square > a(2n)) - a(2n).

Period of length 10: {7,2,6,3,5,4,4,5,3,1}.

Links

Table of n, a(n) for n=1..105.

Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,0,0,0,1).

Formula

a(1)=1, afterwards a(n)=A130532(n+7).

Mathematica

LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 7, 2, 6, 3, 5, 4, 4, 5, 3}, 120] (* or *) PadRight[ {}, 120, {1, 7, 2, 6, 3, 5, 4, 4, 5, 3}] (* Harvey P. Dale, Jul 05 2022 *)

Crossrefs

Cf. A130532.

Sequence in context: A309647 A225444 A379605 * A019934 A295874 A182548

Adjacent sequences: A175405 A175406 A175407 * A175409 A175410 A175411

Keyword

nonn

Author

Zak Seidov, May 03 2010

Status

approved