A140975 Period length 20: repeat 1, 3, 8, 8, 9, 1, 6, 6, 7, 9, 4, 4, 5, 7, 2, 2, 3, 5, 0, 0.

1, 3, 8, 8, 9, 1, 6, 6, 7, 9, 4, 4, 5, 7, 2, 2, 3, 5, 0, 0, 1, 3, 8, 8, 9, 1, 6, 6, 7, 9, 4, 4, 5, 7, 2, 2, 3, 5, 0, 0, 1, 3, 8, 8, 9, 1, 6, 6, 7, 9, 4, 4, 5, 7, 2, 2, 3, 5, 0, 0

Offset

0,2

Comments

The period contains each digit from 0 to 9 twice.

Links

Table of n, a(n) for n=0..59.

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

Formula

a(n) = A011377(n) mod 10.

a(n) = +a(n-1) -a(n-2) +a(n-3) -a(n-4) +a(n-5) -a(n-6) +a(n-7) -a(n-8) +a(n-9) -a(n-10) +a(n-11) -a(n-12) +a(n-13) -a(n-14) +a(n-15) -a(n-16) +a(n-17) -a(n-18) +a(n-19).

G.f.: ( -1 -2*x -6*x^2 -7*x^4 -12*x^6 -13*x^8 +4*x^9 -8*x^10 -9*x^12 +2*x^13 -5*x^16 -2*x^3 +4*x^11 +2*x^15 +6*x^5 +6*x^7 -4*x^14 ) / ( (x-1) *(1+x^2) *(1+x+x^2+x^3+x^4) *(1-x+x^2-x^3+x^4) *(1-x^2+x^4-x^6+x^8) ). - R. J. Mathar, Jul 08 2011

Crossrefs

Cf. A011377.

Sequence in context: A131596 A332892 A371137 * A065481 A354222 A032538

Adjacent sequences: A140972 A140973 A140974 * A140976 A140977 A140978

Keyword

nonn,easy,less

Author

Paul Curtz, Jul 28 2008

Status

approved