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.

A235161 Primes which have one or more occurrences of exactly nine different digits.

Original entry on oeis.org

102345689, 102345697, 102345869, 102346789, 102346879, 102346897, 102346957, 102347689, 102348679, 102348769, 102349867, 102354689, 102354697, 102356489, 102356789, 102356987, 102358769, 102358967, 102364859, 102364879, 102365897, 102365947, 102368459
Offset: 1

Views

Author

Colin Barker, Jan 04 2014

Keywords

Comments

The first term having a repeated digit is 1002346589.

Crossrefs

Programs

  • PARI
    s=[]; forprime(n=100000000, 102400000, if(#vecsort(eval(Vec(Str(n))),,8)==9, s=concat(s, n))); s

A133191 Smallest prime containing all digits except n.

Original entry on oeis.org

1123465789, 203457869, 103456789, 1012458679, 102356789, 102346789, 1012345987, 102345689, 102345697, 1012356487
Offset: 0

Views

Author

Lekraj Beedassy, Dec 17 2007

Keywords

Examples

			We have a(5) = 102346789 because this is the first almost-pandigital prime followed by 102346879, 102346897, 102347689, 102348679, 102348769, 102349867, 102364879, ... all devoid of digit 5.
		

Crossrefs

Cf. A073643.

Extensions

a(3), a(6), a(9) corrected by Ray Chandler, Mar 06 2009

A255596 Distinct-digit primes that are the concatenation of m and prime(m) for some number m.

Original entry on oeis.org

23, 47, 613, 1237, 1759, 27103, 35149, 45197, 57269, 58271, 61283, 85439, 93487, 145829, 147853, 2371489, 3152087, 3902687, 4062791, 5614073, 5914327, 7405639, 8356421
Offset: 1

Views

Author

Zak Seidov, Mar 25 2015

Keywords

Examples

			The last term is a(23) = 8356421 (prime) because all 7 digits are different and m=835 with 6421=prime(m).
		

Crossrefs

Programs

  • Mathematica
    Select[FromDigits[IntegerDigits@ #~Join~IntegerDigits[Prime@ #]] & /@
    Range@ 1200, PrimeQ@ # && Max@ DigitCount@ # == 1 &] (* Michael De Vlieger, Mar 25 2015 *)

A256339 Distinct-digit primes that are concatenation of prime(m) and m for some m.

Original entry on oeis.org

53, 239, 6719, 7321, 4073561, 6257813, 6521843, 85271063
Offset: 1

Views

Author

Zak Seidov, Mar 25 2015

Keywords

Comments

The last term is a(8) = 85271063 (prime) because all 8 digits are different and m=1063 with 8527=prime(m).

Crossrefs

Subsequence of A029743 (distinct-digit primes).

Programs

  • Mathematica
    Select[FromDigits[IntegerDigits[Prime@ #]~Join~IntegerDigits@ #] & /@
    Range@ 1200, PrimeQ@ # && Max@ DigitCount@ # == 1 &] (* Michael De Vlieger, Mar 25 2015 *)

A227795 For each base, b, beginning with binary, the number of (b-1)-digit primes with one copy of each digit save one.

Original entry on oeis.org

0, 3, 1, 9, 52, 283, 2113, 16142, 145227, 1359133, 15000161, 172888810, 2217146126
Offset: 2

Views

Author

James G. Merickel, Sep 23 2013

Keywords

Comments

Note that only decimal 2, 11 and 19 are representable in some base using a copy of each digit in that base (base 2 for the first and base 3 for the others), as a number written in base b with a single copy of each digit is congruent to either 0 or (b-1)/2 modulo b-1.

Examples

			In base 3, 10, 12 and 21 are primes: Decimal 3, 5 and 7.  In base 4, of the possibilities only 103 is prime: Decimal 19.
		

Crossrefs

Programs

  • PARI
    \\ Starts at base 4 and prints in form 'base:count', bases 2 and 3 done by hand.
    {
    b=4;while(1,
    c=0;for(i=1,b!,perm=numtoperm(b,i);
    if(perm[b-1]!=1,
    if(gcd(b,perm[1]-1)==1,
    if(gcd(b-1,perm[b]-1)==1,
    n=sum(j=1,b-1,(perm[j]-1)*b^(j-1));
    if(ispseudoprime(n),c++)))));
    print1(b":"c"\n");b++)
    }

Extensions

a(14) added by James G. Merickel, Oct 14 2013
Showing 1-5 of 5 results.