This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A252739 #17 Dec 20 2015 13:48:21 %S A252739 2,6,720,612360000,1697781042840960000000000, %T A252739 504261397867001013813789115612253942400000000000000000000000000 %N A252739 a(n) = A252738(n) / n. %C A252739 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. %C A252739 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 %F A252739 a(n) = A252738(n) / n. %o A252739 (Scheme) (define (A252739 n) (/ (A252738 n) n)) %Y A252739 Cf. A005245, A005940, A163511, A244743, A252738, A252740, A252741. %K A252739 nonn %O A252739 1,1 %A A252739 _Antti Karttunen_, Dec 21 2014