A252739 a(n) = A252738(n) / n.

2, 6, 720, 612360000, 1697781042840960000000000, 504261397867001013813789115612253942400000000000000000000000000

Offset: 1

Author

Antti Karttunen, Dec 21 2014

Keywords

• nonn

Comments

Note how 6, 720 and 612360000 occur in A244743 as its 0th, 4th and 8th term, from which my bold conjecture that A244743(12) or A244743(16) = 1697781042840960000000000.

According to preliminary results from Janis Iraids, the value of A005245(a(5)) = ||1697781042840960000000000|| = 160, while ||1697781042840960000000000 - 1|| = 169, which lays to rest my naive conjecture above, as 169 - 160 is neither 12 nor 16. Note also how 5, 719 and 612359999 are all primes, while a(5)-1 factorizes as 1697781042840959999999999 = 13 * 89443 * 908669 * 1606890407869. - Antti Karttunen, Dec 20 2015

Crossrefs

Cf. A005245, A005940, A163511, A244743, A252738, A252740, A252741.

Programs

Scheme

(define (A252739 n) (/ (A252738 n) n))

Formula

a(n) = A252738(n) / n.