A037681 Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,3,2.

1, 4, 19, 78, 313, 1252, 5011, 20046, 80185, 320740, 1282963, 5131854, 20527417, 82109668, 328438675, 1313754702, 5255018809, 21020075236, 84080300947, 336321203790, 1345284815161, 5381139260644, 21524557042579, 86098228170318

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base
• easy

Links

• Index entries for linear recurrences with constant coefficients, signature (4,0,0,1,-4).

Programs

Mathematica

Table[FromDigits[PadRight[{},n,{1,0,3,2}],4],{n,30}] (* or *) LinearRecurrence[{4,0,0,1,-4},{1,4,19,78,313},30] (* Harvey P. Dale, May 10 2023 *)

Formula

G.f.: x*(1+3*x^2+2*x^3) / ( (x-1)*(4*x-1)*(1+x)*(x^2+1) ). - R. J. Mathar, May 04 2015