A128040 a(n) = product of the primes which are <= the n-th squarefree positive integer. a(n) also is the LCM of the first n squarefree positive integers.

1, 2, 6, 30, 30, 210, 210, 2310, 30030, 30030, 30030, 510510, 9699690, 9699690, 9699690, 223092870, 223092870, 6469693230, 6469693230, 200560490130, 200560490130, 200560490130, 200560490130, 7420738134810, 7420738134810

Offset

1,2

Links

Table of n, a(n) for n=1..25.

Maple

A005117 := proc(n) option remember; local a; if n =1 then 1; else a := A005117(n-1)+1 ; while not numtheory[issqrfree](a) do a := a+1 ; od: RETURN(a) ; fi ; end: A128040 := proc(n) lcm( seq(A005117(i), i=1..n) ) ; end: seq(A128040(n), n=1..30) ; # R. J. Mathar, Nov 01 2007

Crossrefs

Cf. A034386, A005117.

Sequence in context: A095198 A126989 A361492 * A219196 A233358 A241557

Adjacent sequences: A128037 A128038 A128039 * A128041 A128042 A128043

Keyword

nonn

Author

Leroy Quet, May 07 2007

Extensions

More terms from R. J. Mathar, Nov 01 2007

Status

approved