login
A236365
Primes whose binary and octal representation are also prime when read in decimal.
6
3, 5, 89, 179, 199, 367, 383, 443, 523, 659, 947, 1097, 1163, 1289, 1483, 1753, 2351, 2423, 2903, 3041, 3217, 3299, 3631, 4729, 4951, 5119, 5347, 5879, 6007, 6131, 6491, 6911, 7547, 7577, 7649, 8167, 8849, 9241, 9511, 9817, 9929, 10303, 10831, 11251, 11527
OFFSET
1,1
LINKS
EXAMPLE
89 is prime and appears in the sequence: 89 in binary = 1011001 and in octal = 131, which are also prime when read in decimal.
MAPLE
KD := proc() local a, b, d; a:=ithprime(n); b:=convert(a, binary); d:=convert(a, octal); if isprime(b) and isprime(d) then RETURN (a) ; fi; end: seq(KD(), n=1..50);
MATHEMATICA
t = {}; n = 1; While[Length[t] < 50, n = NextPrime[n]; If[PrimeQ[FromDigits[IntegerDigits[n, 8]]] && PrimeQ[FromDigits[IntegerDigits[n, 2]]], AppendTo[t, n]]]; t (* T. D. Noe, Jan 26 2014 *)
Select[Prime[Range[1400]], AllTrue[FromDigits/@{IntegerDigits[ #, 2], IntegerDigits[ #, 8]}, PrimeQ]&](* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 30 2018 *)
CROSSREFS
Cf. A000040 (prime numbers), A065720 (primes: binary representation is also prime).
Sequence in context: A082715 A133660 A271925 * A057663 A056244 A173487
KEYWORD
nonn,base
AUTHOR
K. D. Bajpai, Jan 23 2014
STATUS
approved