OFFSET
1,1
COMMENTS
Numbers with an abundance of -42.
7454198513685 is also in the sequence. - Alexander Violette, Jan 10 2021
Numbers of the form 2^k * (2^(k + 1) + 41) are in the sequence if and only if 2^(k + 1) + 41 is prime. - David A. Corneth, Jan 15 2021
PROG
(PARI) for(n=1, 100000000, if(((sigma(n)-2*n)==-42), print1(n, ", ")))
(PARI) is(n)=2*n-sigma(n)==42 \\ Charles R Greathouse IV, Jan 11 2021
(PARI) list(lim)=my(v=List()); forfactored(n=1, lim\1, if(2*n[1]-sigma(n)==42, listput(v, n[1]))); Vec(v) \\ Charles R Greathouse IV, Jan 11 2021
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Jason G. Wurtzel, Aug 24 2010
EXTENSIONS
a(10) from Alexander Violette, Jan 10 2021
a(11) from Charles R Greathouse IV, Jan 15 2021
STATUS
approved