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A136424 Floor((x^n - (1-x)^n)/2 +.5) where x = (sqrt(6)+1)/2. +0
1
1, 1, 2, 4, 6, 11, 19, 32, 55, 95, 164, 283, 488, 842, 1451, 2503, 4318, 7447, 12844, 22152, 38207, 65898, 113657, 196029, 338101, 583137, 1005763, 1734685, 2991888, 5160244, 8900104, 15350410, 26475540, 45663552, 78757977, 135837417 (list; graph; listen)
OFFSET

1,3

COMMENT

This is analogous to the closed form of the formula for the n-th Fibonacci

number. Even before truncation, these numbers are rational and the decimal

part always ends in 5. For x=(sqrt(6)+1)/2, a(n)/a(n-1) -> x.

FORMULA

The general form of x is (sqrt(r)+1)/2, r=1,2,3..

PROGRAM

(PARI) g(n, r) = for(m=1, n, print1(fib(m, r)", ")) fib(n, r) = x=(sqrt(r)+1)/2; floor((x^n-(1-x)^n)/sqrt(r)+.5)

CROSSREFS

Adjacent sequences: A136421 A136422 A136423 this_sequence A136425 A136426 A136427

Sequence in context: A140443 A115992 A115993 this_sequence A116732 A048239 A000786

KEYWORD

nonn

AUTHOR

Cino Hilliard (hillcino368(AT)hotmail.com), Apr 01 2008

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Last modified January 7 17:35 EST 2009. Contains 152824 sequences.


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