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A072343
a(n) = 2^(n-1) * Sum_{k=0..n} (n+k)! / k!^2.
0
3, 28, 320, 4272, 65632, 1149312, 22712832, 501216000, 12225264128, 326574262272, 9478749110272, 296914161754112, 9979741990993920, 358151267772203008, 13664955628675399680, 552220995731872481280
OFFSET
1,1
CROSSREFS
Sequence in context: A199754 A277507 A176335 * A292845 A212032 A352383
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Jul 31 2002
STATUS
approved