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A249910
Digital root of A003500(n).
0
2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4, 2, 4, 5, 7, 5, 4
OFFSET
0,1
COMMENTS
Periodic with cycle of length 6: {2,4,5,7,5,4}. a(n) may be expressed as the decimal expansion of 246/1001. Sequence is palindromic.
FORMULA
a(n) = 4*a(n-1) - a(n-2), reduced to digital root.
a(n) = digital root of (2 + sqrt(3))^n + ( 2 - sqrt(3))^n.
MATHEMATICA
LinearRecurrence[{1, 0, -1, 1}, {2, 4, 5, 7}, 102] (* Ray Chandler, Jul 25 2016*)
CROSSREFS
Sequence in context: A257433 A005532 A026202 * A025511 A224367 A308219
KEYWORD
nonn,base
AUTHOR
Peter M. Chema, Dec 17 2014
EXTENSIONS
More terms from Ray Chandler, Jul 25 2016
STATUS
approved