A172430 - OEIS

%I #8 Dec 12 2023 07:43:49

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

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

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

%N Period length 10: repeat 2,1,6,7,0,3,4,9,8,5 .

%C Also the decimal expansion of the rational number 240781665 / 1111111111 .

%F a(n) = A172285(n+1) mod 10.

%F G.f.: (2+x+6*x^2+7*x^3+3*x^5+4*x^6+9*x^7+8*x^8+5*x^9)/ ((1-x) * (1+x) * (x^4+x^3+x^2 +x+1)* (x^4-x^3+x^2-x+1)).

%F a(3*n) = A172423(n+2).

%K nonn,easy

%O 0,1

%A _Paul Curtz_, Feb 02 2010

%E Edited by _R. J. Mathar_, Feb 11 2010