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.

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A368034 Pandigital primes that are the concatenation of 7 primes.

Original entry on oeis.org

23401589677, 23401675789, 23401675897, 23401756789, 23401767589, 23401896757, 23415780961, 23415809761, 23415896017, 23415897601, 23416017589, 23416075789, 23417809561, 23418095761, 23475601789, 23475809761, 23476018957, 23540176789, 23540178967, 23541601789
Offset: 1

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Author

Keywords

Comments

To be prime, a pandigital must use at least 11 digits. There are 4397 pandigital primes with 11 digits that can be cut into 7 prime-chunks.

Examples

			a(1) = 23401589677 can be cut into the 7 prime-chunks 2,3,401,5,89,67,7;
a(2) = 23401675789 can be cut into the 7 prime-chunks 2,3,401,67,5,7,89; etc.
		

Crossrefs

A368035 Pandigital primes that are the concatenation of 8 primes.

Original entry on oeis.org

1032341589677, 1032341758967, 1032343678957, 1032343758967, 1032343767589, 1032347617589, 1032347675897, 1032347789567, 1032347896157, 1032354161897, 1032354178967, 1032354189761, 1032354361789, 1032354378967, 1032354389767, 1032354761897, 1032354767897, 1032356174189, 1032356747897, 1032356778941
Offset: 1

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Author

Keywords

Comments

The least prime number that can be cut into 8 prime-chunks has at least 13 digits. There are in total 875653 such 13-digit primes.

Examples

			a(1) = 1032341589677 can be cut into the 8 prime-chunks 103,2,3,41,5,89,67,7;
a(2) = 1032341758967 can be cut into the 8 prime-chunks 103,2,3,41,7,5,89,67; etc.
		

Crossrefs

A368044 Pandigital primes that are the concatenation of 9 primes.

Original entry on oeis.org

103132343589761, 103132343675897, 103132343761589, 103132343789561, 103132343895677, 103132343895767, 103132357614389, 103132357674389, 103132357894361, 103132361743589, 103132367743589, 103132367754389, 103132367894357, 103132367895743, 103132374358961, 103132375674389
Offset: 1

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Keywords

Comments

The least prime number that can be cut into 9 prime-chunks has at least 15 digits. There are 3764 sets of 9 prime-chunks that produce in total 69061759 primes with 15 digits.

Examples

			a(1) = 103132343589761 can be cut into the 9 prime-chunks 103, 13, 2, 3, 43, 5, 89, 7, 61;
a(2) = 103132343675897 can be cut into the 9 prime-chunks 103, 13, 2, 3, 43, 67, 5, 89, 7; etc.
		

Crossrefs

A159292 Pandigital emirps.

Original entry on oeis.org

10124389567, 10124563789, 10124597683, 10124635897, 10124673859, 10124687359, 10124695783, 10124735689, 10124795683, 10124867359, 10124958673, 10124965387, 10124965783, 10125364897, 10125693847, 10125749863, 10125784639, 10125938467, 10126387549, 10126457893, 10126498573
Offset: 1

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Author

Lekraj Beedassy, Apr 08 2009

Keywords

Comments

There are 413842 11-digit terms. - Jud McCranie, Jul 03 2013 [in light of the comment below, this was independently computed and confirmed to be correct by Michael S. Branicky, Apr 06 2024]
The above statement [by Jud McCranie] is uncertain, as the contributed b-file was wrong (missing terms) from a(436) on. At this point, one has to consider permutations of 10223456789, before coming back, for n > 495, to permutations of 10123456789 starting with 10231.... - M. F. Hasler, Apr 06 2024

Crossrefs

Cf. A006567 (emirps), A050288 (pandigital primes).

Programs

  • PARI
    L=List(); append(N=10123456789, M=Vecsmall([2,3,3]))=forperm(digits(N),p, cmp(p[3..5],M)>0 && break; isprime(P=fromdigits(Vec(p)))&& isprime(fromdigits(Vecrev(p)))&& listput(L, P))
    append(); append(10223456789); #A159292=Set(L) \\ M. F. Hasler, Apr 05 2024
    
  • Python
    from sympy import isprime
    from itertools import count, islice, product
    def emirp(s):
        r = s[::-1]
        return r != s and isprime(int(s)) and isprime(int(r))
    def agen(): # generator of terms
        for d in count(11):
            for f in "1379":
                for m in product("0123456789", repeat=d-2):
                    for e in "1379":
                        t = f + "".join(m) + e
                        if len(set(t)) == 10 and emirp(t):
                            yield int(t)
    print(list(islice(agen(), 100))) # Michael S. Branicky, Apr 09 2024

Formula

Intersection of A006567 and A050288. - M. F. Hasler, Apr 05 2024

Extensions

Erroneous terms corrected and more terms from M. F. Hasler, Apr 05 2024

A159569 Pandigital primes that become zeroless pandigital primes when the digit 0 is deleted.

Original entry on oeis.org

10123465789, 10123685749, 10123746859, 10123854679, 10123945687, 10123956487, 10124356789, 10124378569, 10124563987, 10124568793, 10124683759, 10124695783, 10124736859, 10124763589, 10124785639, 10124867539, 10124867593, 10124935687, 10125367849, 10125368749
Offset: 1

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Author

Lekraj Beedassy, Apr 15 2009

Keywords

Crossrefs

Programs

  • PARI
    remz(d) = {nd = []; for (i=1, #d, if (d[i] != 0, nd = concat(nd, d[i]))); subst(Pol(nd), x, 10);}
    isok(n) = isprime(n) && (d=digits(n)) && (#vecsort(d,,8)==10) && isprime(remz(d));
    lista() = forprime(n=10123465789,, if (isok(n), print1(n, ", "))); \\ Michel Marcus, Oct 06 2014

Extensions

Missing terms a(2)-a(6) and a(15)-a(20) added by Hiroaki Yamanouchi, Oct 06 2014

A168334 Pandigital palindromic primes.

Original entry on oeis.org

1023456987896543201, 1023458697968543201, 1023459768679543201, 1023469587859643201, 1023489657569843201, 1023497568657943201, 1023549678769453201, 1023568794978653201, 1023568947498653201
Offset: 1

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Author

Lekraj Beedassy, Nov 23 2009

Keywords

Comments

Intersection of A050288 and A002385.

Crossrefs

Programs

  • PARI
    {n=1011111111111111101; p=vector(8,i,if(i<8,10^i*10)+10^(17-i))~; a=[]; for(k=0,8!, ispseudoprime(n+numtoperm(8,k)*p) & a=concat(a,n+numtoperm(8,k)*p)); a=vecsort(a)} \\ M. F. Hasler, Dec 07 2009

Extensions

More terms from M. F. Hasler, Dec 07 2009

A225295 Pandigital numbers with exactly 4 prime factors (with multiplicity).

Original entry on oeis.org

1023456987, 1023458679, 1023458967, 1023465798, 1023465897, 1023465978, 1023465987, 1023467589, 1023467859, 1023468579, 1023468597, 1023468795, 1023469758, 1023478569, 1023479586, 1023479865, 1023485967, 1023486579, 1023486957, 1023487659, 1023487965, 1023489657, 1023495678
Offset: 1

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Author

Jonathan Vos Post, May 04 2013

Keywords

Examples

			a(1) = 1023456987 = 3^2 * 7 * 16245349.
a(2) = 1023458679 = 3^3 * 37905877.
a(3) = 1023458967 = 3^2 * 113 * 1006351.
a(4) = 1023465897 = 3^2 * 6379 * 17827.
a(5) = 1023465987 = 3^2 * 53 * 2145631.
a(511032) = 10123456987 = 7^2 * 9833 * 21011.
		

Crossrefs

Cf. A050288 (pandigital primes), A175845 (pandigital numbers).
Cf. A171102 (3-almost primes).

Programs

Formula

A014613 INTERSECTION A171102.
a(n) ~ 6n log n / (log log n)^3. - Charles R Greathouse IV, May 04 2013

Extensions

a(6)-a(23) from Charles R Greathouse IV, May 04 2013

A358020 Least prime number > prime(n) (n >= 5) whose set of decimal digits coincides with the set of decimal digits of prime(n), or -1 if no such prime exists.

Original entry on oeis.org

1111111111111111111, 31, 71, 191, 223, 229, 113, 73, 4111, 433, 4447, 353, 599, 661, 677, 1117, 337, 97, 383, 8999, 797, 10111, 1013, 701, 1009, 131, 271, 311, 173, 193, 419, 1151, 571, 613, 617, 317, 197, 811, 199, 1193, 719, 911, 2111, 233, 277, 929, 2333, 293, 421, 521, 2557
Offset: 5

Views

Author

Jean-Marc Rebert, Oct 24 2022

Keywords

Examples

			prime(6) = 13 and the prime number 31 have the same set of digits {1,3}, and 31 is the smallest such number, hence a(6) = 31.
prime(13) = 41 and the prime number 4111 have the same set of digits {1,4}, and 4111 is the smallest such number, hence a(13) = 4111.
prime(20) = 71 and the prime number 1117 have the same set of digits {1,7}, and 1117 is the smallest such number, hence a(20) = 1117.
		

Crossrefs

Programs

  • Maple
    N:= 60: # for a(5)..a(N)
    A:= Array(5..N):
    R:= 1111111111111111111:
    A[5]:= R: count:= 1:
    for k from 6 while count < N-4 do
      p:= ithprime(k);
      S:= convert(convert(p,base,10),set);
      if assigned(V[S]) and V[S]<=N then A[V[S]]:= p; count:=count+1;  fi;
      V[S]:= k;
    od:
    convert(A,list); # Robert Israel, Oct 25 2022
  • PARI
    a(n)=my(m=Set(digits(prime(n)))); if(n<5, return()); if(n==5,return(1111111111111111111));forprime(p=prime(n+1), , if(Set(digits(p))==m, return(p)))
    
  • Python
    from sympy import isprime, prime
    from itertools import count, product
    def a(n):
        pn = prime(n)
        s = str(pn)
        for d in count(len(s)):
            for p in product(set(s), repeat=d):
                if p[0] == "0": continue
                t = int("".join(p))
                if t > pn and isprime(t):
                    return t
    print([a(n) for n in range(5, 56)]) # Michael S. Branicky, Oct 25 2022

A371361 The first of two consecutive primes p, q such that p, q and p + q are all pandigital.

Original entry on oeis.org

10234568791, 10234685971, 10234756849, 10234786589, 10234865779, 10235678449, 10237845649, 10243756981, 10245836789, 10245936781, 10245968371, 10247658389, 10247658923, 10247685893, 10248357659, 10248756893, 10256734879, 10256839447, 10256839477, 10257384679, 10257486913, 10258367429, 10258367489
Offset: 1

Views

Author

Robert Israel, Mar 19 2024

Keywords

Comments

The first case where a(n) and a(n+1) are consecutive primes is n = 18. Thus p = a(18) = 10256839447, q = a(19) = 10256839477 and r = 10256839487 are three consecutive primes with p, q, r, p + q and q + r all pandigital. In addition, p + r = 20513678934 ia pandigital.

Examples

			a(3) =  10234756849 is a term because it is prime and pandigital, the next prime 10234756859 is also pandigital, and  10234756849 + 10234756859 = 20469513708 is pandigital.
		

Crossrefs

Programs

  • Maple
    ispd:= proc(n) convert(convert(n,base,10),set) = {$0..9} end proc:
    q:=nextprime(10^10): qgood:= false: Res:= NULL: count:= 0:
    while count < 25 do
      p:= q; pgood:= qgood;
      q:= nextprime(p); qgood:= ispd(q);
      if pgood and qgood and ispd(p+q) then
        Res:= Res, p; count:= count+1;
      fi;
    od:
    Res;

A332265 a(n) is the number of prime numbers created when concatenating all the arrangements of the decimal integers from 0 to 3*n+4.

Original entry on oeis.org

20, 3202, 2056675, 3500185228
Offset: 0

Views

Author

Scott R. Shannon, May 04 2020

Keywords

Comments

Only 4 and every third integer after 4 can create primes when concatenating the integer arrangements of 0,...,3*n+4 as the other integer values will create numbers with digit sums divisible by 3, and hence are divisible by 3. The digit 0 is allowed to be the first digit in the number but is then ignored when determining if the remaining digits form a prime.

Examples

			a(0) = 20 as there are twenty primes created when concatenating the integer arrangements of 0,1,2,3,4. They are 1423, 2143, 2341, 4231, 10243, 12043, 20143, 20341, 20431, 23041, 24103, 30241, 32401, 40123, 40213, 40231, 41023, 41203, 42013, 43201.
a(1) = 3202. The smallest prime created using integers 0..7 is 1234657 while the largest is 76540231.
a(2) = 2056675. The smallest prime created using integers 0..10 is 10123457689 while the largest is 987654310021.
		

Crossrefs

Programs

  • Mathematica
    Table[Count[FromDigits /@  Flatten /@ IntegerDigits /@ Permutations[Range[0, 3 n + 4]], ?PrimeQ], {n, 0, 2}] (* _Robert Price, Sep 16 2020 *)
    (* OR, if the above runs low on memory to store all the Permutations at once... *)
    Table[p0 = Range[0, 3n+4]; p = NextPermutation[p0]; c = 0;
     While[p != p0,
      If[PrimeQ[FromDigits[Flatten[IntegerDigits /@ p]]], c++];
    p = NextPermutation[p]]; c, {n, 0, 2}] (* Robert Price, Sep 16 2020 *)

Extensions

a(3) from Giovanni Resta, May 04 2020
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