A218707 - OEIS

A218707

First number beginning the smallest chain of n consecutive even divisors distanced no more than 2 one from each other, with no odd divisors between, of some factorial s!.

%I #16 Nov 07 2012 11:07:56

%S 2,4,4,6,304,680,1054,1558,15904,41638,82800,241898,241898,241898,

%T 241898

%N First number beginning the smallest chain of n consecutive even divisors distanced no more than 2 one from each other, with no odd divisors between, of some factorial s!.

%C Minimal s are respectively : 2, 4, 4, 5, 31, 43, 59, 157, 379, 631, 2179, 2479, 2479, 2479, 2479.

%C Maximal s are : 2, 4, 4, 5, 61 - 1, 53 - 1, 71 - 1, 223 - 1 , 1061 - 1, 661 - 1, 2671 - 1, 4937 - 1, 4937 - 1, 4937 - 1, 4937 - 1.

%e 6, 8, 10, 12 is the smallest chain of length 4 of even divisors of factorials s! with no odd divisor between, for only s = 5.

%Y Cf. A218493.

%K nonn

%O 1,1

%A _Robin Garcia_, Nov 04 2012