OFFSET
1,1
COMMENTS
Note that the number of even divisors s is necessarily a multiple of the number of odd divisors r.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 12 since r = 2, s = 4, t = r + s = 6.
MATHEMATICA
oddtau[n_] := DivisorSigma[0, n/2^IntegerExponent[n, 2]]; seqQ[n_] := Module[{d = DivisorSigma[0, n], o = odd[n]}, EvenQ[d] && EvenQ[o] && Divisible[n, d] && Divisible[n, o] && Divisible[n, d - o]]; Select[Range[2, 2320, 2], seqQ] (* Amiram Eldar, Jan 15 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Walter Kehowski, Jun 25 2006
STATUS
approved