A133927 - OEIS

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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.

1, 30, 494, 6331, 36851, 95450, 122614, 940745, 5126032, 7519204 (list; graph; refs; listen; history; 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	`Eric Weisstein's World of Mathematics, Catalan Number`
	CROSSREFS	`Cf. A000108.` `Sequence in context: A004416 A125487 A127544 * A082556 A036223 A022658` `Adjacent sequences: A133924 A133925 A133926 * A133928 A133929 A133930`
	KEYWORD	`hard,more,nonn`
	AUTHOR	`Ryan Propper (rpropper(AT)cs.stanford.edu), Jan 07 2008`

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Last modified February 14 17:05 EST 2012. Contains 205642 sequences.