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A134718 Even Motzkin numbers. 1
2, 4, 2188, 5798, 113634, 310572, 6536382, 18199284, 25669818476, 73007772802, 114988706524270, 330931069469828, 556704809728838604, 1614282136160911722, 39532221379621112004, 114956499435014161638, 2837208756709314025578 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

COMMENTS

The values of n such that the Motzkin number M(n) (=A001006(n)) is even are given in A081706. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 07 2007

REFERENCES

E. Deutsch and B. E. Sagan, Congruences for Catalan and Motzkin numbers and related sequences, J. Num. Theory 117 (2006), 191-215.

MAPLE

M:=proc(n) options operator, arrow: sum(binomial(n, 2*k)*binomial(2*k, k)/(k+1), k=0..n) end proc: a:=proc(n) if `mod`(M(n), 2)=0 then M(n) else end if end proc: seq(a(n), n=0..50); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 07 2007

CROSSREFS

Cf. A001006.

Cf. A081706.

Sequence in context: A045647 A102064 A085638 * A048829 A070655 A006263

Adjacent sequences:  A134715 A134716 A134717 * A134719 A134720 A134721

KEYWORD

easy,nonn

AUTHOR

Omar E. Pol (info(AT)polprimos.com), Nov 11 2007

EXTENSIONS

More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Dec 07 2007

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Last modified February 15 16:49 EST 2012. Contains 205824 sequences.