A249910 - OEIS

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A249910

Digital root of A003500(n).

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

(list; graph; refs; listen; history; text; internal format)

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.

LINKS

Table of n, a(n) for n=0..101.

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

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