A056607 a(n) is the n-th primorial divided by squarefree kernel of corresponding central binomial coefficient.

2, 3, 10, 35, 231, 3003, 14586, 138567, 5311735, 154040315, 434113615, 16062203755, 354604036745, 15247973580035, 286661903304658, 7596540437573437, 79093391614735197, 4824696888498847017

Offset

1,1

Links

Table of n, a(n) for n=1..18.

Formula

a(n) = A002110(n)/A048633(n).

Example

n=6, A002110(6)=30030, C(6,3)=20 with squarefree kernel 10. So a(6) = 30030/10 = 3003 = 3*7*11*13, also squarefree.

Prog

(PARI) a(n) = prod(k=1, n, prime(k))/factorback(factor(binomial(n, n\2))[, 1]); \\ Michel Marcus, Jul 13 2018

Crossrefs

Cf. A002110, A001405, A048633.

Sequence in context: A356926 A134959 A270367 * A278051 A060604 A075890

Adjacent sequences: A056604 A056605 A056606 * A056608 A056609 A056610

Keyword

nonn

Author

Labos Elemer, Aug 07 2000

Status

approved