280540

Appears in sequences

• Smaller of an amicable pair: (a,b) such that sigma(a) = sigma(b) = a+b, a < b.at n=22A002025
• Number of ways to place 3 nonattacking queens on an n X n toroidal board.at n=12A172518
• Conjectured list of smallest terms of k-sociable cycles of order r.at n=32A183016
• Number of ways to place 3 nonattacking nightriders on an n X n toroidal board.at n=12A196813
• Abundant numbers whose aliquot sequence is abundant, deficient, abundant, ..., etc.at n=31A234969
• Amicable pairs.at n=44A259180
• Amicable pairs (x < y) ordered by nondecreasing sum (x + y) and then by increasing x.at n=44A259933
• Smaller of amicable pair (x, y) as they are listed in A259933.at n=22A260086
• Amicable pairs of even numbers.at n=34A262622
• Even amicable numbers.at n=34A262624
• Amicable numbers (m, n) with record low values of m/n.at n=2A287011
• Amicable pairs with the property that the number of divisors of the smaller member is greater than the number of divisors of the larger member.at n=24A328063
• Lesser of recursive amicable numbers pair: numbers m < k such that m = s(k) and k = s(m), where s(k) = A333926(k) - k is the sum of proper recursive divisors of k.at n=22A333929
• Lesser of amicable pair a < b such that the ratio of their number of divisors d(a)/d(b) sets a new record.at n=1A339680