%I
%S 1264460,2115324,2784580,7169104,18656380,28158165,81128632,174277820,
%T 498215416,1236402232,1799281330,2387776550,2717495235,2879697304,
%U 15837081520,17616303220,91411869465,111375706442,661126361272,741158497112
%N Smallest member of sociable quadruples with signature: abundant, abundant, deficient, deficient.
%C Members of a sociable quadruple are usually listed in the order with which they appear in the corresponding aliquot sequence. Therefore, in a sociable quadruple the 1st member is abundant, and the 4th member is deficient. In all, we can get 4 possibilities, and a sociable quadruple can be (with A for abundant, and D for deficient) : AADD, ADDD, ADAD, AAAD. The numbers in these sequences have been voluntarily limited to 12 digits maximum, the current status of the exhaustive search (see Pedersen link).
%H J. M. Pedersen, <a href="http://amicable.homepage.dk/knwnc4.htm">Known Sociable Numbers of order four</a>
%e The first quadruple of this type is: 1264460, 1547860, 1727636, 1305184, that are respectively abundant, abundant, deficient, deficient.
%Y Cf. A090615, A222976, A222977, A222978.
%K nonn
%O 1,1
%A _Michel Marcus_, Mar 11 2013
