a(0) = 13 a(1) = 1439 a(2) = 100799 a(3) = 3548879 a(4) = 14061599 a(5) = 38342303 a(6) = 120355199 a(7) = 12555446399 a(8) <= 144129585599 a(9) <= 1140135796799 a(10) <= 10175362797599 a(11) <= 17482966300799 a(12) <= 121622472971999 a(13) <= 121159394848799 a(14) <= 1157798453011199 a(15) <= 359892368035199 a(16) <= 1131641635924799 a(17) <= 1126617501239999 a(18) <= 1481660442662399 a(19) <= 1238694415358399 a(20) <= 12132114354359999 a(21) <= 13667267630015999 a(22) <= 111469583968142399 a(23) <= 125707504216694399 a(24) <= 139277357803583999 a(25) <= 159798227315126399 a(26) <= 121915385803411199 a(27) <= 136172654313695999 a(28) <= 136615077395596799 a(29) <= oo a(30) <= 1417080564409910399