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Search: id:A124431
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A124431 a(n) = Sum_{k=0..n} 2^k*C([(n+k)/2],k)*C([(n+k+1)/2],k)). +0
1
1, 3, 9, 29, 97, 331, 1145, 4001, 14089, 49915, 177713, 635293, 2278841, 8198227, 29567729, 106872961, 387038993, 1404052659, 5101219929, 18559193245, 67605310097, 246541193883, 899999057385, 3288522934433, 12026324883865 (list; graph; listen)
OFFSET

0,2

FORMULA

a(n) = Sum_{k=0..n} 2^k*A124428(n+k,k).

PROGRAM

(PARI) a(n)=sum(k=0, n, 2^k*binomial((n+k)\2, k)*binomial((n+k+1)\2, k))

CROSSREFS

Cf. A124428.

Adjacent sequences: A124428 A124429 A124430 this_sequence A124432 A124433 A124434

Sequence in context: A071732 A071736 A082306 this_sequence A071740 A081696 A077587

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Oct 31 2006

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Last modified October 7 08:31 EDT 2008. Contains 144667 sequences.


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