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A099571 Sum C(n-k+3,k), k=0..floor(n/2). 2
1, 1, 5, 6, 17, 23, 50, 73, 138, 211, 370, 581, 979, 1560, 2575, 4135, 6755, 10890, 17700, 28590, 46356, 74946, 121380, 196326, 317797, 514123, 832025, 1346148, 2178293, 3524441, 5702870, 9227311, 14930334, 24157645, 39088150, 63245795 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

Fourth column of triangle A054450.

LINKS

Table of n, a(n) for n=0..35.

Index entries for linear recurrences with constant coefficients, signature (1,4,-3,-6,3,4,-1,-1).

FORMULA

G.f.: 1/((1-x^2)^3*(1-x-x^2)); a(n)=a(n-1)+4a(n-2)-3a(n-3)-6a(n-4)+3a(n-5)+4a(n-6)-a(n-7)-a(n-8); a(n)=sum{k=0..n, F(n-k+1)*binomial(k/2+2, 2)(1+(-1)^k)/2}.

CROSSREFS

Cf. A054451, A052952, A099572, A000045.

Sequence in context: A059013 A191144 A035595 * A041997 A041773 A041054

Adjacent sequences:  A099568 A099569 A099570 * A099572 A099573 A099574

KEYWORD

easy,nonn

AUTHOR

Paul Barry, Oct 23 2004

STATUS

approved

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Last modified May 21 09:11 EDT 2019. Contains 323441 sequences. (Running on oeis4.)