A273969 - OEIS

A273969

Numbers n such that there exists a pair x,y, where x<y, x! = n and y! = n, that makes {x,y,n,n} an amicable multiset.

%I #16 Jul 27 2016 21:54:14

%S 702240,817740,1156680,1159200,1811040,2450448,2570400,2784600,

%T 3534300,3912480,4228560,4546080,4702320,5682600,6902280,7280280,

%U 7469280,7706160,8225280,8316000,8465184,8522640,8639400,9025380,9256800,9282000,9492120,9828000

%N Numbers n such that there exists a pair x,y, where x<y, x! = n and y! = n, that makes {x,y,n,n} an amicable multiset.

%C We call the multiset {x,y,n,n} amicable iff sigma(x) = sigma(y) = sigma(n) = x+y+n+n. For the x values, see A273970. For the y values, see A273971.

%C If the condition x<y were dropped, the terms from A259306 would also belong here.

%H John Cerkan, <a href="/A273969/b273969.txt">Table of n, a(n) for n = 1..8082</a>

%H John Cerkan, <a href="/A273969/a273969.py.txt">Python code</a>

%e sigma(695520) = sigma(803040) = sigma(702240) = 695520 + 803040 + 702240 + 702240.

%Y Cf. A259302, A259303, A259304, A259305, A259306, A273970, A273971.

%K nonn

%O 1,1

%A _John Cerkan_, Jul 17 2016