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A102071 Pairwise sums of general ballot numbers (A002026). 2
1, 3, 7, 17, 42, 106, 272, 708, 1865, 4963, 13323, 36037, 98123, 268737, 739833, 2046207, 5682915, 15842505, 44315637, 124348275, 349911204, 987212856, 2791964574, 7913642086, 22477090679, 63964370301, 182353459733 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

FORMULA

G.f.: 4z(1+z)/[1-z+sqrt(1-2z-3z^2)]^2.

CROSSREFS

First differences of A005554. Partial sums of A026269.

Sequence in context: A086395 A020730 A003440 * A191627 A178778 A161943

Adjacent sequences:  A102068 A102069 A102070 * A102072 A102073 A102074

KEYWORD

nonn

AUTHOR

Ralf Stephan, Dec 30 2004

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Last modified February 13 18:01 EST 2012. Contains 205532 sequences.