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A133927 Numbers n such that the sum of the first n Catalan numbers, C_1 + C_2 + ... + C_n, is divisible by n. 0
1, 30, 494, 6331, 36851, 95450, 122614, 940745, 5126032, 7519204 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sum of the first 30 Catalan numbers, 1 + 2 + 5 + ... + 3814986502092304 = 5175497420902740, is divisible by 30, so 30 is a term.

No more terms < 5*10^7. [Lars Blomberg, Nov 07 2011]

LINKS

Table of n, a(n) for n=1..10.

Eric Weisstein's World of Mathematics, Catalan Number

CROSSREFS

Cf. A000108.

Sequence in context: A258417 A212473 A127544 * A082556 A036223 A022658

Adjacent sequences:  A133924 A133925 A133926 * A133928 A133929 A133930

KEYWORD

hard,more,nonn

AUTHOR

Ryan Propper, Jan 07 2008

STATUS

approved

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Last modified May 26 00:02 EDT 2020. Contains 334612 sequences. (Running on oeis4.)