A061083 Fibonacci-type sequence based on division: a(0) = 1, a(1) = 2 and a(n) = a(n-2)/a(n-1) but ignore decimal point.

1, 2, 5, 4, 125, 32, 390625, 8192, 476837158203125, 17179869184, 277555756156289135105907917022705078125, 618970019642690137449562112

Offset

0,2

Links

Reinhard Zumkeller, Table of n, a(n) for n = 0..17

Formula

a(n) = k^(n-th Fibonacci number) with k=2 if n is odd, k=5 if n is even

Example

a(6) = 390625, since a(4)/a(5) = 125/32 = 3.90625

Prog

(Haskell)
a061083 n = a061083_list !! n
a061083_list = 1 : 2 : zipWith divIgnPnt a061083_list (tail a061083_list)
   where divIgnPnt x y = ddiv (10 * m) x' where
            ddiv u w | r == 0    = 10 * w + q
                     | otherwise = ddiv (10 * r) (10 * w + q)
                     where (q, r) = divMod u y
            (x', m) = divMod x y
-- Reinhard Zumkeller, Dec 29 2011

Crossrefs

Cf. A061084 for subtraction, A000301 for multiplication and A000045 for addition - the common Fibonacci numbers

Sequence in context: A307131 A210419 A206484 * A177039 A075102 A209883

Adjacent sequences: A061080 A061081 A061082 * A061084 A061085 A061086

Keyword

nonn,easy,nice,base

Author

Ulrich Schimke (ulrschimke(AT)aol.com)

Status

approved