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A066974 Integers of the form (1/m)*sum(i=1,m,binomial(2i,i)). 0
2, 4, 70, 2197, 86944, 305045, 184940110, 480921672850, 1390639119568762, 13871716673121190349872, 46286334476836197400150816, 158305268738561655232891129492, 552015921314537446560239006496196 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

MATHEMATICA

Select[Table[Sum[Binomial[2i, i]/m, {i, m}], {m, 60}], IntegerQ] (* Harvey P. Dale, Dec 23 2014 *)

CROSSREFS

Sequence in context: A301818 A054920 A062061 * A270583 A018373 A292414

Adjacent sequences:  A066971 A066972 A066973 * A066975 A066976 A066977

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Jan 26 2002

STATUS

approved

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Last modified June 16 21:55 EDT 2021. Contains 345080 sequences. (Running on oeis4.)