Quasiamicable Pair
Let
be the divisor
function of
. Then two numbers
and
are a quasiamicable
pair if
The first few are (48, 75), (140, 195), (1050, 1925), (1575, 1648), ... (OEIS A005276). Quasiamicable numbers are sometimes called betrothed numbers or reduced amicable pairs.
5, 12, 13 triangle