A130875 Absolute difference of final digits of two consecutive cubes.

1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1, 1, 3, 1, 7, 9, 1, 7, 1, 3, 1

Offset

1,2

Comments

Periodic with period 10.

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(n) = a(n-10). - Colin Barker, Dec 04 2014

G.f.: -x*(9*x^9+7*x^8+x^7+3*x^6+x^5+x^4+3*x^3+x^2+7*x+1) / ((x-1)*(x+1)*(x^4-x^3+x^2-x+1)*(x^4+x^3+x^2+x+1)). - Colin Barker, Dec 04 2014

Mathematica

LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 7, 1, 3, 1, 1, 3, 1, 7, 9}, 105] (* Ray Chandler, Aug 26 2015 *)
Abs[Differences[Mod[#, 10]]]&/@Partition[Range[0, 120]^3, 2, 1]//Flatten (* or *) PadRight[{}, 120, {1, 7, 1, 3, 1, 1, 3, 1, 7, 9}] (* Harvey P. Dale, Oct 27 2019 *)

Prog

(PARI) Vec(-x*(9*x^9+7*x^8+x^7+3*x^6+x^5+x^4+3*x^3+x^2+7*x+1)/((x-1)*(x+1)*(x^4-x^3+x^2-x+1)*(x^4+x^3+x^2+x+1)) + O(x^100)) \\ Colin Barker, Dec 04 2014

Crossrefs

Cf. A008960.

Sequence in context: A266985 A286912 A239807 * A370112 A200923 A317830

Adjacent sequences: A130872 A130873 A130874 * A130876 A130877 A130878

Keyword

base,easy,nonn

Author

Giovanni Teofilatto, Jul 25 2007

Status

approved