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
KEYWORD
nonn
AUTHOR
Omar E. Pol, Feb 17 2008
STATUS
approved