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A030132 Digital root of Fibonacci(n). 12
0, 1, 1, 2, 3, 5, 8, 4, 3, 7, 1, 8, 9, 8, 8, 7, 6, 4, 1, 5, 6, 2, 8, 1, 9, 1, 1, 2, 3, 5, 8, 4, 3, 7, 1, 8, 9, 8, 8, 7, 6, 4, 1, 5, 6, 2, 8, 1, 9, 1, 1, 2, 3, 5, 8, 4, 3, 7, 1, 8, 9, 8, 8, 7, 6, 4, 1, 5, 6, 2, 8, 1, 9, 1, 1, 2, 3, 5, 8, 4, 3, 7, 1, 8, 9, 8, 8 (list; graph; refs; listen; history; internal format)
OFFSET

0,4

COMMENTS

Every other (a(0),a(1)) pair of nonzero digits enters a cycle of length 24, except for (3,3) which enters a cycle of length 8 and (9,9) which is periodic of length 1. - Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 29 2005

REFERENCES

S. Marivani and others, Problem 10974, Amer. Math. Monthly, 111 (No. 7, 2004), 628.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 0..10000

Colm Mulcahy, Gibonacci Bracelets.

Marc Renault, The Fibonacci sequence modulo m

FORMULA

a(n+1) = sum of digits of (a(n) + a(n-1)).

Periodic with period 24 given by {1, 1, 2, 3, 5, 8, 4, 3, 7, 1, 8, 9, 8, 8, 7, 6, 4, 1, 5, 6, 2, 8, 1, 9}

a(n+1) = sum of digits of (a(n) + a(n-1)). a(n+1) = A007953(a(n) + a(n-1)). - Jonathan Vos Post (jvospost3(AT)gmail.com), Dec 29 2005

a(n) + a(n+1) = A010077(n+4); a(A017641(n)) = 9. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 04 2007

MATHEMATICA

digitalRoot[n_Integer?Positive] := FixedPoint[Plus@@IntegerDigits[#]&, n]; Table[If[n==0, 0, digitalRoot[Fibonacci[n]]], {n, 0, 100}] (* From Vladimir Joseph Stephan Orlovsky, May 02 2011 *)

PROG

(Haskell)

a030132 n = a030132_list !! n

a030132_list =

   0 : 1 : map a007953 (zipWith (+) a030132_list (tail a030132_list))

-- Reinhard Zumkeller, Aug 20 2011

CROSSREFS

Cf. A000045 (Fibonacci numbers), A010888 (digital roots), A004090, A007953, A030133.

Sequence in context: A098906 A007887 A105472 * A004090 A104205 A166015

Adjacent sequences:  A030129 A030130 A030131 * A030133 A030134 A030135

KEYWORD

nonn,base,easy,nice

AUTHOR

youngelder(AT)webtv.net (Ana)

EXTENSIONS

Entry revised by N. J. A. Sloane (njas(AT)research.att.com), Aug 29 2004

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Last modified February 14 08:58 EST 2012. Contains 205614 sequences.