A080664 - OEIS

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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

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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

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-François Alcover, Jul 04 2013

STATUS

approved