Numbers whose sum of digits s equals its product of digits and s + 1 and s - 1 are both prime.

Terms

a(0) =4a(1) =6a(2) =22a(3) =123a(4) =132a(5) =213a(6) =231a(7) =312a(8) =321a(9) =111126a(10) =111162a(11) =111216a(12) =111261a(13) =111612a(14) =111621a(15) =112116a(16) =112161a(17) =112611a(18) =116112a(19) =116121a(20) =116211a(21) =121116a(22) =121161a(23) =121611a(24) =126111a(25) =161112a(26) =161121a(27) =161211a(28) =162111a(29) =211116