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A079284 Diagonal sums of triangle A008949. 2
1, 1, 3, 4, 9, 13, 26, 39, 73, 112, 201, 313, 546, 859, 1469, 2328, 3925, 6253, 10434, 16687, 27633, 44320, 72977, 117297, 192322, 309619, 506037, 815656, 1329885, 2145541, 3491810 (list; graph; refs; listen; history; internal format)
OFFSET

0,3

COMMENTS

a(2n)-a(2n-1)=Fib(2n+1)

Diagonal sums of triangle A054450. - Paul Barry (pbarry(AT)wit.ie), Oct 23 2004

FORMULA

a(n)=sum(sum(binomial(n-j, i), i, 0, j), j, 0, floor(n/2))

a(n) = Fibonacci(n+3)-2^floor((n+1)/2). - Vladeta Jovovic (vladeta(AT)eunet.rs), Feb 12 2003

G.f.: (1-x^2)/((1-x-x^2)(1-2x^2)); - Paul Barry (pbarry(AT)wit.ie), Jan 13 2005

MAPLE

with (combinat):a[0]:=0:a[1]:=1:a[2]:=1:for n from 2 to 50 do a[n]:=fibonacci(n-1)+2*a[n-2] od: seq(a[n], n=1..31); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Mar 17 2008

CROSSREFS

Cf. A008949, A000045, A079284.

Cf. A061667, A005672.

Cf. A102517.

Sequence in context: A124285 A131326 A089300 * A000624 A056514 A151517

Adjacent sequences:  A079281 A079282 A079283 * A079285 A079286 A079287

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Feb 08 2003

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Last modified February 16 04:47 EST 2012. Contains 205860 sequences.