OFFSET
1,1
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..500
EXAMPLE
47940 is in the sequence because sigma(47940)=145152, sigma(47941)=48384, and 145152=3*48384.
7749060 is in the sequence because sigma(7749060)=24192000, sigma(7749061)=8064000, and 24192000=3*8064000.
MAPLE
MATHEMATICA
Position[Partition[DivisorSigma[1, Range[78*10^5]], 2, 1], _?(#[[1]] == 3#[[2]]&), {1}, Heads->False]//Flatten (* Harvey P. Dale, Oct 17 2016 *)
PROG
(Magma) [n: n in [1..10^7] | SumOfDivisors(n) eq 3*SumOfDivisors(n+1)]; // Bruno Berselli, Mar 25 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Paolo P. Lava, Mar 25 2013
EXTENSIONS
More terms from Bruno Berselli, Mar 25 2013
STATUS
approved