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A138807 a(n) = floor: Pi*a(n-1) + a(n-2). 0
0, 1, 3, 10, 37, 128, 439, 1508, 5179, 17779, 61033, 209522, 719266, 2469165, 8476377, 29098491, 99891986, 342918422, 1177201983, 4041207525, 13873029857, 47624616207, 163490174266, 561244146614 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

a(n)/a(n-1) tends to 3.4328922159... = exp ArcSinh(Pi/2).

FORMULA

a(n) = floor: Pi*a(n-1) * a(n-2); a(0) = 0, a(1) = 1; n>1. a(n) = floor of terms (1,2) and (2,2) of the 2 X 2 matrix [0,1; 1,Pi]^n

EXAMPLE

a(4) = 37 since [0,1; 1,Pi]^4 = [10.869..., 37.289...; 37.289..., 128.017...].

CROSSREFS

Sequence in context: A010373 A104603 A080625 * A149043 A151315 A164048

Adjacent sequences:  A138804 A138805 A138806 * A138808 A138809 A138810

KEYWORD

nonn

AUTHOR

Gary W. Adamson (qntmpkt(AT)yahoo.com), Mar 30 2008

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Last modified February 16 05:55 EST 2012. Contains 205860 sequences.