A340467 a(n) is the n-th squarefree number having n primes.

2, 10, 66, 462, 4290, 53130, 903210, 17687670, 406816410, 11125544430, 338431883790, 11833068917670, 457077357006270, 20384767656323070, 955041577211912190, 49230430891074322890, 2740956243836856315270, 168909608387276001835590, 11054926927790884163355330

Offset

1,1

Comments

a(n) is the n-th product of n distinct primes.

All terms are even.

This sequence differs from A073329 which has also nonsquarefree terms.

Links

Alois P. Heinz, Table of n, a(n) for n = 1..350

Formula

a(n) = A340316(n,n).

a(n) = A005117(m) <=> A072047(m) = n = A340313(m).

A001221(a(n)) = A001222(a(n)) = n.

a(n) < A070826(n+1), the least odd number with exactly n distinct prime divisors.

Example

a(1) = A000040(1) = 2.
a(2) = A006881(2) = 10.
a(3) = A007304(3) = 66.
a(4) = A046386(4) = 462.
a(5) = A046387(5) = 4290.
a(6) = A067885(6) = 53130.
a(7) = A123321(7) = 903210.
a(8) = A123322(8) = 17687670.
a(9) = A115343(9) = 406816410.
a(10) = A281222(10) = 11125544430.

Crossrefs

Main diagonal of A340316.

Cf. A001221, A001222, A005117, A070826, A072047, A073329, A101695, A340313.

Cf. A000040, A006881, A007304, A046386, A046387, A067885, A123321, A123322, A115343, A281222.

Sequence in context: A064170 A151410 A230050 * A278459 A278461 A027307

Adjacent sequences: A340464 A340465 A340466 * A340468 A340469 A340470

Keyword

nonn

Author

Alois P. Heinz, Jan 08 2021

Status

approved