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A212792 Product of all primes in the interval ((n+1)/2,n]. 2
1, 2, 3, 3, 5, 5, 35, 35, 7, 7, 77, 77, 143, 143, 143, 143, 2431, 2431, 46189, 46189, 4199, 4199, 96577, 96577, 7429, 7429, 7429, 7429, 215441, 215441, 6678671, 6678671, 392863, 392863, 392863, 392863, 765049, 765049, 765049, 765049, 31367009, 31367009, 1348781387 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The case n=1 is special and defined conventionally.

a(n) = A034386(n)/A034386(1+floor((n+1)/2)).

Notice that the interval is semiopen; a prime p is included in the product if (n+1)<2p<=2n.

LINKS

Stanislav Sykora, Table of n, a(n) for n = 1..1000

EXAMPLE

a(13) = product of all primes in (7,13] = 11*13 = 143.

PROG

(PARI:){p2(n) = result=1; forprime(p=1+floor((n+1)\2), n, result=result*p); }

CROSSREFS

Cf. A212791, A034386.

Sequence in context: A106530 A273156 A294487 * A281363 A050976 A053447

Adjacent sequences:  A212789 A212790 A212791 * A212793 A212794 A212795

KEYWORD

nonn

AUTHOR

Stanislav Sykora, May 27 2012

STATUS

approved

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Last modified December 7 09:33 EST 2019. Contains 329843 sequences. (Running on oeis4.)