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A124217 Expansion of (1-x-x^2)/(1-2x-x^2+x^4). +0
2
1, 1, 2, 5, 11, 26, 61, 143, 336, 789, 1853, 4352, 10221, 24005, 56378, 132409, 310975, 730354, 1715305, 4028555, 9461440, 22221081, 52188297, 122569120, 287865097, 676078233, 1587833266, 3729175645, 8758319459, 20569736330 (list; graph; listen)
OFFSET

0,3

COMMENT

Diagonal sums of generalized Pascal triangle A124216.

FORMULA

a(n)=sum{k=0..floor(n/2), sum{j=0..n-k, C(n-k,j)C(j,2(j-k))2^(j-k)}};

CROSSREFS

Adjacent sequences: A124214 A124215 A124216 this_sequence A124218 A124219 A124220

Sequence in context: A026787 A064416 A006138 this_sequence A095981 A082397 A051286

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Oct 19 2006

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Last modified November 9 12:23 EST 2009. Contains 166233 sequences.


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