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A081395 a(n)=x is the smallest value such that number of non-unitary prime divisors of a(n)-th Catalan number, A000108(x)=C(2x,x)/(x+1) equals n. 2
1, 6, 13, 25, 72, 96, 182, 320, 481, 923, 1018, 1321, 1323, 1670, 3457, 3455, 3472, 3464, 3462, 3469, 8222, 9991 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..21.

FORMULA

a(n) = Min{x; A081389(x)=n}.

EXAMPLE

n=6: a(6)=182, C(364,182)/183 has 6 non-unitary prime divisors: {2,3,7,11,17,19} and 182 is the smallest.

CROSSREFS

Cf. A000108, A081389, A081393, A081394.

Sequence in context: A101736 A162432 A117072 * A192762 A268721 A183337

Adjacent sequences:  A081392 A081393 A081394 * A081396 A081397 A081398

KEYWORD

nonn,more

AUTHOR

Labos Elemer, Mar 27 2003

EXTENSIONS

a(11)-a(21) from Michel Marcus, Sep 01 2019

STATUS

approved

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Last modified July 10 15:45 EDT 2020. Contains 335577 sequences. (Running on oeis4.)