Prime numbers p where d(p-1) = d(p+1) increases to a record.

Terms

a(0) =7a(1) =19a(2) =41a(3) =199a(4) =919a(5) =5741a(6) =18089a(7) =41651a(8) =90271a(9) =446081a(10) =1276001a(11) =27033161a(12) =43220449a(13) =53308529a(14) =109245401a(15) =512669249a(16) =663929729a(17) =2266639649a(18) =2560742911a(19) =2969200961a(20) =8505402751a(21) =32540473601a(22) =61573368401a(23) =74335064959a(24) =109494811999