OFFSET
1,1
COMMENTS
EXAMPLE
10 is in the sequence because the sum of divisors of 10 is less than (2*10 - 1). The sum of divisors of 10 is 1 + 2 + 5 + 10 = 18 and 2*10 - 1 = 19.
MATHEMATICA
Select[Range[120], DivisorSigma[1, #]<2#-1&] (* Harvey P. Dale, Sep 12 2018 *)
PROG
(PARI) s=[]; for(n=1, 200, if(sigma(n)<2*n-1, s=concat(s, n))); s \\ Colin Barker, Feb 20 2014
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Omar E. Pol, Feb 19 2014
STATUS
approved