219295

Appears in sequences

• Numbers k such that sigma(triangular(k)) = sigma(k)^2.at n=16A232355
• Numbers k with the property that it is possible to write the base 2 expansion of k as concat(a_2,b_2), with a_2>0 and b_2>0 such that, converting a_2 and b_2 to base 10 as a and b, we have sigma(a + b) = sigma(k).at n=34A258843