Smallest member of sociable quadruples.

Terms

a(0) =1264460a(1) =2115324a(2) =2784580a(3) =4938136a(4) =7169104a(5) =18048976a(6) =18656380a(7) =28158165a(8) =46722700a(9) =81128632a(10) =174277820a(11) =209524210a(12) =330003580a(13) =498215416a(14) =1236402232a(15) =1799281330a(16) =2387776550a(17) =2717495235a(18) =2879697304a(19) =3705771825a(20) =4424606020a(21) =4823923384a(22) =5373457070a(23) =8653956136