A135618 Even Motzkin numbers divided by 2.

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.

Links

Table of n, a(n) for n=1..17.

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

Cf. A001006, A134718.

Sequence in context: A247072 A282293 A252358 * A241921 A340290 A119554

Adjacent sequences: A135615 A135616 A135617 * A135619 A135620 A135621

Keyword

nonn

Author

Omar E. Pol, Feb 17 2008

Status

approved