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A301600 a(n) = Primorial(n) / Product_{k prime<n} k. 0
1, 2, 6, 15, 35, 385, 1001, 17017, 46189, 1062347, 30808063, 955049953, 3212440751, 131710070791, 435656388001, 20475850236047, 1085220062510491, 64027983688118969, 229747470880897477, 15393080549020130959, 57521511525285752531, 4199070341345859934763, 331726556966322934846277 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Sum_{n>=0} 1/a(n) = 1.765582555581609270...

LINKS

Table of n, a(n) for n=0..22.

FORMULA

a(0)=1, for n > 0 a(n) = A002110(n) / A034386(n-1).

EXAMPLE

a(5) = 2*3*5*7*11 / 2*3 = 385.

PROG

(PARI) a(n) = prod(k=1, n, prime(k))/prod(k=1, n-1, if (isprime(k), k, 1)); \\ Michel Marcus, Mar 26 2018

CROSSREFS

Cf. A002110, A034386.

Sequence in context: A153517 A136302 A116404 * A084860 A084798 A215149

Adjacent sequences:  A301597 A301598 A301599 * A301601 A301602 A301603

KEYWORD

nonn

AUTHOR

Pedro Caceres, Mar 24 2018

STATUS

approved

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Last modified October 13 18:57 EDT 2019. Contains 327981 sequences. (Running on oeis4.)