[seqfan] A178526 Fibonacci Triangle, and A001595

Peter Lawrence peterl95124 at sbcglobal.net
Tue Aug 7 06:03:57 CEST 2012


I stumbled[*] on an alternate definition for A178526 "Fibonacci  
Triangle",
and for A001595.

using the naive recursion F(n) = F(n-1) + F(n-2),  F(0) = 1, F(1) = 1,

T [r, c ] = number of times F(c) is evaluated when computing F(r)

for example the 4'th row is

	1, 1, 2, 3, 2

indicating that F(4) is evaluated 1 times
                 F(3)              1
                 F(2)              2
                 F(1)              3
and             F(0)              2

you can also get this from the "fibonacci tree" by simply counting
the number of occurrences of each number/label in the tree, without
the complication of giving weights to edges.


when you add up all the numbers in a row you get A001595,
which now can be interpreted as the total number of function calls
in evaluating the recursive Fibonacci formula.


Peter Lawrence.


[* by "stumbled" I mean I started with these definitions and found
    that the sequences already existed !]



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