OFFSET

1,1

COMMENTS

The first term, 30514, is also a number k such that k and k + 1 have the sum divisors in Gaussian integers: -54720 + 48960*i (where i is the imaginary unit). What is the next term with this property?

No more terms below 1.5*10^10.

MATHEMATICA

csigma[n_] :=(Abs @ DivisorSigma[1, n, GaussianIntegers -> True])^2; seq = {}; n1 = csigma[1]; Do[n2 = csigma[n]; If[n1 == n2, AppendTo[seq, n - 1]]; n1 = n2, {n, 2, 5*10^5}]; seq

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Amiram Eldar, Feb 09 2020

STATUS

approved