A366369 a(n) = product of primes p such that p^k <= n < 2*p^k for some k >= 1.

1, 1, 2, 6, 6, 30, 10, 70, 70, 210, 42, 462, 462, 6006, 858, 858, 858, 14586, 4862, 92378, 92378, 92378, 8398, 193154, 193154, 965770, 74290, 222870, 222870, 6463230, 6463230, 200360130, 200360130, 200360130, 11785890, 11785890, 11785890, 436077930, 22951470, 22951470, 22951470, 941010270, 941010270

Offset: 0

Author

Max Alekseyev, Oct 08 2023

Keywords

• nonn

Crossrefs

Subsequence of A005117.

Cf. A003418, A139550, A366368.

Programs

PARI

a366369(n) = my(r=1); forprime(p=2, n, if(n<2*p^logint(n,p), r*=p)); r;

Formula

a(n) = A003418(n) / A139550(n) = A003418(n) / A003418(floor(n/2)).

a(n) = A003418(n)^2 / A366368(n).