login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A153787 Largest proper divisor of Motzkin number A001006(n). 0
1, 2, 3, 7, 17, 1, 19, 167, 1094, 2899, 1, 13945, 56817, 155286, 284489, 785593, 3268191, 9099642, 16950673, 47515853, 133587741, 225952083, 456103971, 75994979, 6417454619, 1921257179, 1944142787, 187477987, 1697385471211 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..30.

MAPLE

with(numtheory): M := proc (n) options operator, arrow: (sum((-1)^j*binomial(n+1, j)*binomial(2*n-3*j, n), j = 0 .. floor((1/3)*n)))/(n+1) end proc: seq(divisors(M(i))[tau(M(i))-1], i = 2 .. 32); # Emeric Deutsch, Jan 18 2009

CROSSREFS

Cf. A001006, A032742, A152766, A152982.

Sequence in context: A034732 A000278 A270525 * A141795 A077322 A174359

Adjacent sequences:  A153784 A153785 A153786 * A153788 A153789 A153790

KEYWORD

nonn

AUTHOR

Omar E. Pol, Jan 16 2009

EXTENSIONS

Extended by Emeric Deutsch, Jan 18 2009

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 21 20:59 EDT 2019. Contains 322328 sequences. (Running on oeis4.)