A180598 Digital root of 8n.

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

Offset: 0

Author

Odimar Fabeny, Sep 10 2010

Keywords

• easy
• nonn
• base
• changed

Comments

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

Essentially the same as A138531. - R. J. Mathar, Jul 09 2011

Links

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

Crossrefs

Cf. A007953, A010888, A180592 - A180599.

Programs

Mathematica

f[n_] := Mod[8 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Sep 20 2010 *)

Formula

G.f.: -x*(9*x^8+x^7+2*x^6+3*x^5+4*x^4+5*x^3+6*x^2+7*x+8)/((x-1)*(x^2+x+1)*(x^6+x^3+1)). - Colin Barker, Aug 19 2012

a(n) = A010888(8*n). - R. J. Mathar, Aug 28 2025

Extensions

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