Primes having only {1, 2, 4} as digits.

Terms

a(0) =2a(1) =11a(2) =41a(3) =211a(4) =241a(5) =421a(6) =2111a(7) =2141a(8) =2221a(9) =2411a(10) =2441a(11) =4111a(12) =4211a(13) =4241a(14) =4421a(15) =4441a(16) =11411a(17) =12211a(18) =12241a(19) =12421a(20) =14221a(21) =14411a(22) =21121a(23) =21211a(24) =21221a(25) =22111a(26) =22441a(27) =24121a(28) =24421a(29) =41141