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

Author

Giovanni Teofilatto, Jul 25 2007

Keywords

• base
• easy
• nonn

Comments

Periodic with period 10.

Links

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

Crossrefs

Cf. A008960.

Programs

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 *)

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

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