A020452 Primes that contain digits 1 and 4 only.

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

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

David W. Wilson

Status

approved