OFFSET
0,2
COMMENTS
The period contains each digit from 0 to 9 twice.
LINKS
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
KEYWORD
nonn,easy,less
AUTHOR
Paul Curtz, Jul 28 2008
STATUS
approved