A180592 Digital root of 2n.

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

Offset

0,2

Comments

Period 9. - Robert G. Wilson v, Sep 20 2010

Also digital root of A002276(n). - Enrique Pérez Herrero, Nov 05 2022

Links

Table of n, a(n) for n=0..104.

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

Formula

From R. J. Mathar, Nov 02 2010: (Start)

a(n) = A010888(2*n).

a(n) = a(n-9), n > 9.

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

Mathematica

f[n_] := Mod[2 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Sep 20 2010 *)

Prog

(PARI) a(n)=if(n, (2*n-1)%9+1, 0) \\ Charles R Greathouse IV, Aug 25 2014

Crossrefs

Cf. A007953, A010888, A180593, A180594, A180595, A180596, A180597, A180598, A180599.

Sequence in context: A032763 A146082 A169909 * A004092 A133311 A088402

Adjacent sequences: A180589 A180590 A180591 * A180593 A180594 A180595

Keyword

easy,nonn,base

Author

Odimar Fabeny, Sep 10 2010

Extensions

More terms from Robert G. Wilson v, Sep 20 2010

Keyword:base and formulas from R. J. Mathar, Nov 02 2010

Status

approved