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A135618
Even Motzkin numbers divided by 2.
0
1, 2, 1094, 2899, 56817, 155286, 3268191, 9099642, 12834909238, 36503886401, 57494353262135, 165465534734914, 278352404864419302, 807141068080455861, 19766110689810556002, 57478249717507080819, 1418604378354657012789
OFFSET
1,2
REFERENCES
E. Deutsch and B. E. Sagan, Congruences for Catalan and Motzkin numbers and related sequences, J. Num. Theory 117 (2006), 191-215.
FORMULA
a(n)=A134718(n)/2.
MATHEMATICA
#/2&/@Select[Rest[RecurrenceTable[{a[0]==a[1]==1, a[n]==(3(n-1)a[n-2]+ (2n+1)a[n-1])/(n+2)}, a, {n, 60}]], EvenQ] (* Harvey P. Dale, Feb 27 2012 *)
CROSSREFS
Sequence in context: A247072 A282293 A252358 * A241921 A340290 A119554
KEYWORD
nonn
AUTHOR
Omar E. Pol, Feb 17 2008
STATUS
approved