cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A108386 Primes p such that p's set of distinct digits is {1,3,7,9}.

Original entry on oeis.org

1973, 3719, 3917, 7193, 9137, 9173, 9371, 13397, 13799, 13997, 17393, 17939, 19373, 19379, 19739, 19793, 19937, 19973, 31379, 31397, 31793, 31799, 31973, 33179, 33791, 37139, 37199, 37991, 39317, 39371, 39719, 39791, 39971, 71339, 71399
Offset: 1

Views

Author

Rick L. Shepherd, Jun 01 2005

Keywords

Comments

The digits in {1,3,7,9} are the possible ending digits of multidigit primes. [Corrected by Lekraj Beedassy, Apr 04 2009]
Subsequence of A091633. - Michel Marcus, Jun 08 2014

Crossrefs

Cf. A108382 ({1, 3, 7}), A108383 ({1, 3, 9}), A108384 ({1, 7, 9}), A108385 ({3, 7, 9}), A030096 (Primes whose digits are all odd).

A108383 Primes p such that p's set of distinct digits is {1,3,9}.

Original entry on oeis.org

139, 193, 1193, 1319, 1399, 1913, 1931, 1933, 1993, 3119, 3191, 3319, 3391, 3911, 3919, 3931, 9133, 9311, 9319, 9391, 9931, 11393, 11399, 11933, 11939, 13339, 13399, 13913, 13931, 13933, 13999, 19139, 19319, 19333, 19391, 19913, 19993, 31139
Offset: 1

Views

Author

Rick L. Shepherd, Jun 01 2005

Keywords

Crossrefs

Cf. A108382 ({1, 3, 7}), A108384 ({1, 7, 9}), A108385 ({3, 7, 9}), A108386 ({1, 3, 7, 9}), A030096 (Primes whose digits are all odd).

Programs

  • Mathematica
    Select[(Table[FromDigits/@Tuples[{1,3,9},n],{n,3,5}]//Flatten),PrimeQ[#] && Min[ DigitCount[#,10,{1,3,9}]]>0&] (* Harvey P. Dale, Apr 09 2017 *)

A108384 Primes p such that p's set of distinct digits is {1,7,9}.

Original entry on oeis.org

179, 197, 719, 971, 1979, 1997, 7919, 9719, 9791, 11197, 11719, 11779, 11971, 17191, 17791, 17911, 17971, 17977, 19717, 19777, 19979, 19997, 71119, 71191, 71719, 71917, 71971, 71999, 77191, 77719, 79111, 91711, 91771, 91997, 97117, 97171
Offset: 1

Views

Author

Rick L. Shepherd, Jun 01 2005

Keywords

Crossrefs

Cf. A108382 ({1, 3, 7}), A108383 ({1, 3, 9}), A108385 ({3, 7, 9}), A108386 ({1, 3, 7, 9}), A030096 (Primes whose digits are all odd).

Programs

  • Mathematica
    Flatten[Table[Select[FromDigits/@Select[Tuples[{1,7,9},n],Union[#]=={1,7,9}&],PrimeQ],{n,3,5}]] (* Harvey P. Dale, Feb 15 2016 *)
  • PARI
    lista(nn) = forprime(p=179, nn, if(vecsort(digits(p), , 8)==[1, 7, 9], print1(p, ", "))) \\ Iain Fox, Oct 25 2017

A108385 Primes p such that p's set of distinct digits is {3,7,9}.

Original entry on oeis.org

379, 397, 739, 937, 3739, 3779, 3793, 3797, 7393, 7793, 7933, 7937, 7993, 9337, 9377, 9397, 9733, 9739, 9973, 33739, 33797, 33937, 33997, 37339, 37379, 37397, 37799, 37993, 37997, 39373, 39397, 39733, 39779, 39799, 39937, 39979, 73379, 73939
Offset: 1

Views

Author

Rick L. Shepherd, Jun 01 2005

Keywords

Crossrefs

Cf. A108382 ({1, 3, 7}), A108383 ({1, 3, 9}), A108384 ({1, 7, 9}), A108386 ({1, 3, 7, 9}), A030096 (Primes whose digits are all odd).

Programs

  • Mathematica
    Table[Select[FromDigits/@Select[Tuples[{3,7,9},n],SubsetQ[#,{3,7,9}]&], PrimeQ],{n,3,5}]//Flatten (* Harvey P. Dale, Sep 15 2016 *)

A108388 Transmutable primes: Primes with distinct digits d_i, i=1,m (2<=m<=4) such that simultaneously exchanging all occurrences of any one pair (d_i,d_j), i<>j results in a prime.

Original entry on oeis.org

13, 17, 31, 37, 71, 73, 79, 97, 113, 131, 179, 191, 199, 313, 331, 337, 773, 911, 919, 1171, 1933, 3391, 7717, 9311, 11113, 11119, 11177, 11717, 11933, 33199, 33331, 77171, 77711, 77713, 79999, 97777, 99991, 113111, 131111, 131113, 131171, 131311
Offset: 1

Views

Author

Rick L. Shepherd, Jun 02 2005

Keywords

Comments

a(n) is a term iff a(n) is prime and binomial(m,2) 'transmutations' (see example) of a(n) are different primes. A083983 is the subsequence for m=2: one transmutation (The author of A083983, Amarnath Murthy, calls the result of such a digit-exchange a self-complement. {Because I didn't know until afterwards that this sequence was a generalization of A083983 and as this generalization always leaves some digits unchanged for m>2, I've chosen different terminology.}). A108389 ({1,3,7,9}) is the subsequence for m=4: six transmutations. Each a(n) corresponding to m=3 (depending upon its set of distinct digits) and having three transmutations is also a member of A108382 ({1,3,7}), A108383 ({1,3,9}), A108384 ({1,7,9}), or A108385 ({3,7,9}). The condition m>=2 only eliminates the repunit (A004022) and single-digit primes. The condition m<=4 is not a restriction because if there were more distinct digits, they would include even digits or the digit 5, in either case transmuting into a composite number. Some terms such as 1933 are reversible primes ("Emirps": A006567) and the reverse is also transmutable. The transmutable prime 3391933 has three distinct digits and is also a palindromic prime (A002385). The smallest transmutable prime having four distinct digits is A108389(0) = 133999337137 (12 digits).

Examples

			179 is a term because it is prime and its three transmutations are all prime:
exchanging ('transmuting') 1 and 7: 179 ==> 719 (prime),
exchanging 1 and 9: 179 ==> 971 (prime) and
exchanging 7 and 9: 179 ==> 197 (prime).
(As 791 and 917 are not prime, 179 is not a term of A068652 or A003459 also.).
Similarly, 1317713 is transmutable:
exchanging all 1's and 3s: 1317713 ==> 3137731 (prime),
exchanging all 1's and 7s: 1317713 ==> 7371173 (prime) and
exchanging all 3s and 7s: 1317713 ==> 1713317 (prime).
		

Crossrefs

Cf. A108382, A108383, A108384, A108385, A108386, A108389 (transmutable primes with four distinct digits), A083983 (transmutable primes with two distinct digits), A108387 (doubly-transmutable primes), A006567 (reversible primes), A002385 (palindromic primes), A068652 (every cyclic permutation is prime), A003459 (absolute primes).

Programs

  • Python
    from gmpy2 import is_prime
    from itertools import combinations, count, islice, product
    def agen(): # generator of terms
        for d in count(2):
            for p in product("1379", repeat=d):
                p, s = "".join(p), sorted(set(p))
                if len(s) == 1: continue
                if is_prime(t:=int(p)):
                    if all(is_prime(int(p.translate({ord(c):ord(d), ord(d):ord(c)}))) for c, d in combinations(s, 2)):
                        yield t
    print(list(islice(agen(), 50))) # Michael S. Branicky, Dec 15 2023
Showing 1-5 of 5 results.