The OEIS is supported by the many generous donors to the OEIS Foundation.

 Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 59th year, we have over 358,000 sequences, and we’ve crossed 10,300 citations (which often say “discovered thanks to the OEIS”). Other ways to Give
 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A238090 Primes whose hexadecimal representation contains only consonants. 2
 11, 13, 191, 223, 251, 3019, 3023, 3037, 3067, 3259, 3323, 3517, 3533, 3547, 3581, 3583, 4027, 4091, 4093, 48079, 48091, 48383, 48571, 48589, 49103, 49117, 52189, 52223, 52667, 52733, 53197, 56267, 56269, 56509, 56527, 56543, 56767, 56779, 56783, 56827, 64717, 64763, 769019, 769231, 769243, 769247, 769469, 769487 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Primes whose hexadecimal representation contains only the "digits" B, C, D and F. There are no primes whose hexadecimal representation contains only the vowels A and E (for these would be even numbers greater than 2). LINKS Michael S. Branicky, Table of n, a(n) for n = 1..21472 (all terms with <= 9 hexadecimal digits; terms 1..166 from N. J. A. Sloane) EXAMPLE The first few terms and their hexadecimal representations (written with least significant "digit" on the left) are: 11, [B] 13, [D] 191, [F, B] 223, [F, D] 251, [B, F] 3019, [B, C, B] 3023, [F, C, B] 3037, [D, D, B] 3067, [B, F, B] 3259, [B, B, C] 3323, [B, F, C] ... PROG (Python) from sympy import isprime, primerange def ok(p): return set(hex(p)[2:]) <= set("bcdf") def aupton(limit): return [p for p in primerange(1, limit+1) if ok(p)] print(aupton(769487)) # Michael S. Branicky, Nov 13 2021 (Python) # faster version for going to large numbers from sympy import isprime from itertools import product def auptohd(m): # terms up to m hex digits return [t for t in (int("".join(p), 16) for d in range(1, m+1) for p in product("bcdf", repeat=d)) if isprime(t)] print(auptohd(7)) # Michael S. Branicky, Nov 13 2021 CROSSREFS Cf. A140969. Sequence in context: A144375 A140969 A064759 * A093605 A288304 A155967 Adjacent sequences: A238087 A238088 A238089 * A238091 A238092 A238093 KEYWORD nonn,base AUTHOR N. J. A. Sloane, Feb 19 2014, corrected Feb 20 2014 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 2 20:59 EST 2022. Contains 358510 sequences. (Running on oeis4.)