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A080664 Numbers n such that n-th Catalan number is squarefree. 4
1, 2, 3, 4, 5, 7, 8, 9, 11, 17, 19, 31, 35 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

No more terms < 10000. - Robert G. Wilson v, Aug 28 2004

LINKS

Table of n, a(n) for n=1..13.

C. Rivera, Problem 43. Catalan Numbers in www.primepuzzles.net

MATHEMATICA

Select[Range[500], SquareFreeQ[CatalanNumber[ # ]] &]

CROSSREFS

Cf. A000108.

Sequence in context: A289995 A192137 A192139 * A230762 A098776 A098897

Adjacent sequences:  A080661 A080662 A080663 * A080665 A080666 A080667

KEYWORD

nonn

AUTHOR

Joseph L. Pe, Mar 01 2003

EXTENSIONS

Mathematica updated by Jean-Fran├žois Alcover, Jul 04 2013

STATUS

approved

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Last modified August 18 04:50 EDT 2019. Contains 326072 sequences. (Running on oeis4.)