OFFSET
0,1
COMMENTS
The sequence is periodic with period 12.
LINKS
Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).
FORMULA
EXAMPLE
a(5)=4 because A000032[5]=11 and the digital root of 11*11 = 121 is 4.
MATHEMATICA
LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {4, 1, 9, 7, 4, 4, 9, 4, 4, 7, 9, 1}, 108] (* Ray Chandler, Aug 27 2015 *)
PadRight[{}, 120, {4, 1, 9, 7, 4, 4, 9, 4, 4, 7, 9, 1}] (* Harvey P. Dale, Feb 18 2018 *)
PROG
(PARI)
Vec(-(x^11+9*x^10+7*x^9+4*x^8+4*x^7+9*x^6+4*x^5+4*x^4+7*x^3+9*x^2+x+4)/(x^12-1) + O(x^100))
CROSSREFS
KEYWORD
nonn,easy,base
AUTHOR
Colin Barker, Jan 17 2014
EXTENSIONS
Extended by Ray Chandler, Aug 27 2015
STATUS
approved