OFFSET
1,1
COMMENTS
An even number n with prime factorization Product_i p_i^(e_i) is in this sequence iff Product_i (n*e_i+1)/(e_i+1) is an integer.
This sequence is infinite since A002110(n)^2 / 9 is always a term of this sequence for n > 1.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
4 is a term because 4 = 2^2 and (4*2+1) mod (2+1) = 0.
PROG
(PARI) is(n, f=factor(n))=f=f[, 2]; n%2==0 && denominator(prod(i=1, #f, (f[i]*n+1)/(f[i]+1)))==1 \\ Charles R Greathouse IV, Jul 20 2016
CROSSREFS
KEYWORD
nonn
AUTHOR
Altug Alkan, Jul 20 2016
STATUS
approved