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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!.
0
2, 4, 4, 6, 304, 680, 1054, 1558, 15904, 41638, 82800, 241898, 241898, 241898, 241898
OFFSET
1,1
COMMENTS
Minimal s are respectively : 2, 4, 4, 5, 31, 43, 59, 157, 379, 631, 2179, 2479, 2479, 2479, 2479.
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.
EXAMPLE
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.
CROSSREFS
Cf. A218493.
Sequence in context: A179112 A359119 A096612 * A177153 A164719 A104510
KEYWORD
nonn
AUTHOR
Robin Garcia, Nov 04 2012
STATUS
approved