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A074844
Largest difference between consecutive divisors of n is equal to the sum of divisors of n except 1 and n.
1
4, 345, 6489, 88473
OFFSET
1,1
COMMENTS
No other term < 600000. - Emeric Deutsch, Aug 04 2005
No more terms < 10^9. - Lars Blomberg, Jun 04 2013
If p = 5^k - 2 is a prime > 3, then 3*p*(p+2)/5 is in this sequence (see A109080). - Charlie Neder, Oct 13 2018
a(5) > 10^13. - Giovanni Resta, Feb 15 2020
EXAMPLE
The divisors of 345 are [1, 3, 5, 15, 23, 69, 115, 345] and the largest difference between consecutive divisors is 345-115 = 230; the sum of divisors except 1 and 345 are 3+5+15+23+69+115 = 230.
MAPLE
with(numtheory): a:=proc(n) local div: div:=divisors(n): if max(seq(div[j]-div[j-1], j=2..tau(n)))=sigma(n)-1-n then n else fi end: seq(a(n), n=1..100000); # Emeric Deutsch, Aug 04 2005
CROSSREFS
Sequence in context: A069884 A332134 A283101 * A225207 A052391 A377772
KEYWORD
nonn,more
AUTHOR
Jason Earls, Sep 10 2002
EXTENSIONS
More terms from Emeric Deutsch, Aug 04 2005
STATUS
approved