A134301 Periodic sequence (0, 2, 6, 2, 0).

0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0, 0, 2, 6, 2, 0

Offset: 0

Author

Franz Vrabec, Jan 30 2008

Keywords

• nonn
• easy

Comments

Also: twice the partial sums of A117444. - R. J. Mathar, Feb 01 2008

Links

• Rozsa Peter, Leon Harkleroad, Mathematics is Beautiful, Math. Intellig., 12 (No. 1, 1990), 58-64.
• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,1).

Programs

Mathematica

PadRight[{},70,{0,2,6,2,0}] (* Harvey P. Dale, Mar 22 2012 *)

PARI

a(n)=[0, 2, 6, 2, 0][n%5+1] \\ Charles R Greathouse IV, Jul 13 2016

Formula

a(n) = n(n+1) mod 10

O.g.f.: -2/(x-1)+(2*x^3+2*x^2-2*x-2)/(1+x+x^2+x^3+x^4). a(n)=a(n-5). - R. J. Mathar, Feb 01 2008