The On-Line Encyclopedia of Integer Sequences (OEIS)

A104588 revision #11

A104588

Product of primes less than or equal to sqrt(n).

1, 1, 1, 2, 2, 2, 2, 2, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 30, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210, 210

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OFFSET

1,4

LINKS

Table of n, a(n) for n=1..70.

FORMULA

a(n) = A034386(A000196(n)).

For n>0, #p(n) appears {(p(n+1))^2 - (p(n))^2} times [from n=(p(n))^2 to n=(p(n+1))^2 - 1, inclusive], i.e. A002110(n) appears A069482(n) times [from n=A001248(n) to n=A001248(n+1)-1, inclusive]

MAPLE

A104588 := proc(n)

A034386(A000196(n)) ;

end proc: # R. J. Mathar, Jul 28 2013

PROG

(PARI) a(n) = {pr = 1; forprime (p=2, sqrtint(n), pr *= p; ); return (pr); } \\ Michel Marcus, Jul 28 2013

CROSSREFS

Sequence in context: A221838 A343122 A338869 * A157279 A214080 A278241

Adjacent sequences: A104585 A104586 A104587 * A104589 A104590 A104591

KEYWORD

nonn

AUTHOR

Lekraj Beedassy, Mar 17 2005

STATUS

approved