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 A020452 Primes that contain digits 1 and 4 only. 11
 11, 41, 4111, 4441, 11411, 14411, 41141, 41411, 44111, 1114111, 1144141, 1144441, 1411141, 1411411, 1441411, 1444111, 1444411, 1444441, 4141441, 4414411, 4441111, 4441441, 11111141, 11141111, 11141441, 11441141, 11441411, 14111441, 14141411 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Alois P. Heinz, Table of n, a(n) for n = 1..20000 (first 1000 terms from Vincenzo Librandi) James Maynard and Brady Haran, Primes without a 7, Numberphile video (2019). MATHEMATICA Flatten[Table[Select[FromDigits/@Tuples[{1, 4}, n], PrimeQ], {n, 8}]] (* Vincenzo Librandi, Jul 27 2012 *) PROG (MAGMA) [p: p in PrimesUpTo(14141411) | Set(Intseq(p)) subset [1, 4]]; // Bruno Berselli, Jul 27 2012 (Python) from sympy import primerange def checkd(a, c):     b =  set(int(i) for i in set(str(a)))     return b.issubset(c) for n in primerange(2, 2000000):     if checkd(n, [1, 4]):         print(n) # Abhiram R Devesh, May 08 2015 CROSSREFS Cf. A032822. Sequence in context: A257967 A104118 A159561 * A249413 A003356 A063152 Adjacent sequences:  A020449 A020450 A020451 * A020453 A020454 A020455 KEYWORD nonn,base AUTHOR STATUS approved

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Last modified May 25 22:51 EDT 2022. Contains 354073 sequences. (Running on oeis4.)