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A180597
Digital root of 7n.
8
0, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8, 6, 4, 2, 9, 7, 5, 3, 1, 8
OFFSET
0,2
COMMENTS
Period of 9. - Robert G. Wilson v, Sep 20 2010
FORMULA
G.f.: x*(7 + 5*x + 3*x^2 + x^3 + 8*x^4 + 6*x^5 + 4*x^6 + 2*x^7 + 9*x^8)/(1 - x^9). - Stefano Spezia, Apr 21 2022
a(n) = A010888(A008589(n)). - Michel Marcus, Apr 21 2022
MATHEMATICA
f[n_] := Mod[7 n - 1, 9] + 1; f[0] = 0; Array[f, 105, 0] (* Robert G. Wilson v, Sep 20 2010 *)
PROG
(PARI) a(n)=7*n%9 \\ Charles R Greathouse IV, Aug 22 2014
KEYWORD
easy,nonn,base
AUTHOR
Odimar Fabeny, Sep 10 2010
EXTENSIONS
More terms from Robert G. Wilson v, Sep 20 2010
STATUS
approved