A158570 - OEIS

%I #23 Mar 04 2024 01:09:43

%S 1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,

%T 4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,

%U 1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1,2,4,1,1,2,5,1,1

%N a(n) = A007814((2n-1)!! + 1).

%C Repeats with period 8.

%C Also the decimal expansion of the constant 124112510/99999999. - _R. J. Mathar_, Apr 02 2009

%H <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,1).

%F a(n) = 1 if n == 0,1,4,5 (mod 8),

%F        2 if n ==     2,6 (mod 8),

%F        4 if n ==       3 (mod 8),

%F        5 if n ==       7 (mod 8).

%F G.f.: -x*(1 + 2*x + 4*x^2 + x^3 + x^4 + 2*x^5 + 5*x^6 + x^7)/((x-1)*(1+x)*(x^2+1)*(x^4+1)). - _R. J. Mathar_, Apr 02 2009

%t PadRight[{},120,{1,2,4,1,1,2,5,1}] (* _Harvey P. Dale_, May 05 2020 *)

%Y Cf. A007814, A001147.

%K nonn,easy

%O 1,2

%A _Vladimir Shevelev_, Mar 21 2009