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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A217489 Least positive integer without a digit 1, not listed earlier and not divisible by any digit of the preceding term.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 8, 9, 20, 23, 25, 27, 29, 33, 22, 35, 26, 37, 32, 43, 34, 38, 28, 39, 40, 30, 44, 42, 45, 46, 47, 50, 24, 49, 53, 52, 57, 36, 55, 48, 54, 58, 59, 56, 62, 63, 64, 65, 67, 68, 69, 70, 60, 73, 74, 66, 75, 72, 79, 76, 80, 77, 78, 82, 83, 85, 84, 86, 87, 89, 92, 93, 88, 90
Offset: 1

Views

Author

M. F. Hasler and Eric Angelini, Oct 04 2012

Keywords

Comments

This sequence contains all terms of A052383 that are not divisible by 2520. - Peter Kagey, Nov 04 2015
From Robert Israel, Jan 03 2016: (Start)
Here is a proof of Peter Kagey's comment:
Any number x in A052383 will eventually appear in the sequence if there are infinitely many members of the sequence containing no digit that divides x.
If k in A052383 is coprime to 210 (and thus not divisible by any digit > 1), then k is in the sequence.
The numbers 2...23 with number of 2's not divisible by 3, and 5...57 with number of 5's == 2,4 or 5 (mod 6) are coprime to 210, and thus are in the sequence.
The repunits k...k with k = 5 or 7 and an even number of digits are not divisible by 2 or 3, and thus they are in the sequence.
The repunits k...k with k = 2,3,4,6,8, or 9 and number of digits not divisible by 6 are not divisible by 5 or 7, and thus they are in the sequence. Any x in A052383 not divisible by 2520 is not divisible by one of the digits 2,3,...9, and thus is in the sequence. (End)

Crossrefs

Sequence A217491 is a variant of the same idea (where injectivity is strengthened to strict monotonicity).

Programs

  • Maple
    N:= 1000: # to get all terms before the first that exceeds N
    A[1]:= 2:
    Av:= remove(t -> has(convert(t,base,10),1),{$3..N}):
    for n from 2 do
      d:= convert(convert(A[n-1],base,10),set) minus {0};
      Ad:= remove(t -> ormap(y -> t mod y = 0, d) , Av);
      if nops(Ad) = 0 then break fi;
      A[n]:= min(Ad);
      Av:= Av minus {A[n]};
    od:
    seq(A[i],i=1..n-1); # Robert Israel, Jan 03 2016
  • Mathematica
    a = {2}; Do[k = 1; While[Or[First@ DigitCount@ k > 0, MemberQ[a, k], Total[Boole@ Divisible[k, #] & /@ (IntegerDigits@ a[[n - 1]] /. 0 -> Nothing)] > 0], k++]; AppendTo[a, k], {n, 2, 74}]; a (* Michael De Vlieger, Nov 05 2015 *)

A383749 Positive numbers k whose decimal expansion does not contain the decimal expansion of any proper divisor of k.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 23, 27, 29, 34, 37, 38, 43, 46, 47, 49, 53, 54, 56, 57, 58, 59, 67, 68, 69, 73, 74, 76, 78, 79, 83, 86, 87, 89, 94, 97, 98, 203, 207, 209, 223, 227, 229, 233, 239, 247, 249, 253, 257, 259, 263, 267, 269, 277, 283, 289, 293, 299, 307
Offset: 1

Views

Author

Rémy Sigrist, May 08 2025

Keywords

Comments

Also fixed points of A121042.
This sequence is infinite as it contains A173041.
a(n) > 5 contains no decimal digit 1 and does not end in 2 or 5. - Michael S. Branicky, May 11 2025

Examples

			The proper divisors of 54 are 1, 2, 3, 6, 9, 18 and 27; none of them appear in the decimal expansion of 54 so 54 belongs to this sequence.
		

Crossrefs

A038603 and A173041 are subsequences.

Programs

  • Mathematica
    A383749Q[k_] := SelectFirst[Divisors[k], StringContainsQ[IntegerString[k], IntegerString[#]] &] == k;
    Select[Range[500], A383749Q] (* Paolo Xausa, May 12 2025 *)
  • PARI
    is(n, base = 10) = {
        my (d = digits(n, base));
        for (i = 1, #d,
            if (d[i],
                for (j = i, #d,
                    if ((i!=1 || j!=#d) && n % fromdigits(d[i..j], base)==0,
                        return (0);););););
        return (1);}
    
  • Python
    from itertools import count, islice
    from sympy import divisors
    def A383749_gen(startvalue=1): # generator of terms >= startvalue
        return filter(lambda n:not any(dA383749_list = list(islice(A383749_gen(),40)) # Chai Wah Wu, May 10 2025
    
  • Python
    def ok(n):
        s = str(n)
        subs = (s[i:j] for i in range(len(s)) for j in range(i+1, len(s)+1) if s[i]!='0')
        return n and not any(n%v == 0 for ss in subs if n > (v:=int(ss)) > 0)
    print([k for k in range(308) if ok(k)]) # Michael S. Branicky, May 11 2025

A217491 Next largest positive integer without a digit 1 and not divisible by any digit of the preceding term.

Original entry on oeis.org

2, 3, 4, 5, 6, 7, 8, 9, 20, 23, 25, 27, 29, 33, 34, 35, 37, 38, 43, 46, 47, 50, 52, 53, 56, 57, 58, 59, 62, 63, 64, 65, 67, 68, 69, 70, 72, 73, 74, 75, 76, 79, 80, 82, 83, 85, 86, 87, 89, 92, 93, 94, 95, 96, 97, 200, 203, 205, 207, 209, 223, 227, 229, 233, 235, 239, 245, 247, 249
Offset: 1

Views

Author

M. F. Hasler and Eric Angelini, Oct 04 2012

Keywords

Crossrefs

A variant of A217489.
Cf. A038603. - Charles R Greathouse IV, Oct 04 2012

A307636 Numbers k with property that no two divisors of k share a common digit.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 23, 27, 29, 37, 43, 47, 49, 53, 59, 67, 73, 79, 83, 86, 87, 89, 97, 223, 227, 229, 233, 239, 257, 263, 267, 269, 277, 283, 293, 307, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 409, 433, 439, 443, 449, 457, 463, 467, 479, 487, 499, 503
Offset: 1

Views

Author

Giorgos Kalogeropoulos, May 03 2019

Keywords

Examples

			9566 is such a number because its divisors are  1, 2, 4783 and 9566, and no two of them share the same digit.
		

Crossrefs

A038603 is a subsequence.

Programs

  • Maple
    filter:= proc(n) local D,i,j;
      D:= map(t -> convert(convert(t,base,10),set), convert(numtheory:-divisors(n),list));
      for i from 2 to nops(D) do
        for j from 1 to i-1 do
           if D[i] intersect D[j] <> {} then return false fi
      od od;
      true
    end proc:
    select(filter, [$1..1000]); # Robert Israel, Jul 07 2019
  • Mathematica
    Select[Range@1000,!Or@@IntersectingQ@@@Subsets[IntegerDigits@Divisors[#],{2}]&]
  • PARI
    isok(k) = {my(d = divisors(k), dd = apply(x->Set(digits(x)), d)); for (i=1, #dd, for (j=i+1, #dd, if (#setintersect(dd[i], dd[j]), return (0)););); return (1);} \\ Michel Marcus, Jul 07 2019
    
  • Python
    from itertools import count, combinations, islice
    from sympy import divisors
    def A307636gen(): return filter(lambda n:all(len(set(s[0])&set(s[1])) == 0 for s in combinations((str(d) for d in divisors(n,generator=True)),2)),count(1))
    A307636_list = list(islice(A307636gen(),20)) # Chai Wah Wu, Dec 08 2021

A386328 Primes without {1, 2} as digits.

Original entry on oeis.org

3, 5, 7, 37, 43, 47, 53, 59, 67, 73, 79, 83, 89, 97, 307, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 409, 433, 439, 443, 449, 457, 463, 467, 479, 487, 499, 503, 509, 547, 557, 563, 569, 577, 587, 593, 599, 607, 643, 647, 653, 659, 673, 677, 683, 709
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038604.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 3, 4, 5, 6, 7, 8, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 2] == 0 &]
  • PARI
    primes_with(, 1, [0, 3, 4, 5, 6, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("03456789"), 41))) # uses function/imports in A385776
    

A386329 Primes without {1, 3} as digits.

Original entry on oeis.org

2, 5, 7, 29, 47, 59, 67, 79, 89, 97, 227, 229, 257, 269, 277, 409, 449, 457, 467, 479, 487, 499, 509, 547, 557, 569, 577, 587, 599, 607, 647, 659, 677, 709, 727, 757, 769, 787, 797, 809, 827, 829, 857, 859, 877, 887, 907, 929, 947, 967, 977, 997, 2027, 2029, 2069
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038611.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 2, 4, 5, 6, 7, 8, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 3] == 0 &]
  • PARI
    primes_with(, 1, [0, 2, 4, 5, 6, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("02456789"), 41))) # uses function/imports in A385776
    

A386330 Primes without {1, 4} as digits.

Original entry on oeis.org

2, 3, 5, 7, 23, 29, 37, 53, 59, 67, 73, 79, 83, 89, 97, 223, 227, 229, 233, 239, 257, 263, 269, 277, 283, 293, 307, 337, 353, 359, 367, 373, 379, 383, 389, 397, 503, 509, 523, 557, 563, 569, 577, 587, 593, 599, 607, 653, 659, 673, 677, 683, 709, 727, 733, 739
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038612.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 2, 3, 5, 6, 7, 8, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 4] == 0 &]
  • PARI
    primes_with(, 1, [0, 2, 3, 5, 6, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("02356789"), 41))) # uses function/imports in A385776
    

A386331 Primes without {1, 5} as digits.

Original entry on oeis.org

2, 3, 7, 23, 29, 37, 43, 47, 67, 73, 79, 83, 89, 97, 223, 227, 229, 233, 239, 263, 269, 277, 283, 293, 307, 337, 347, 349, 367, 373, 379, 383, 389, 397, 409, 433, 439, 443, 449, 463, 467, 479, 487, 499, 607, 643, 647, 673, 677, 683, 709, 727, 733, 739, 743, 769
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038613.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 2, 3, 4, 6, 7, 8, 9]];
    
  • Maple
    f:= n-> (l-> add([0, $2..4, $6..9][l[j]+1]*10^(j-1), j=1..nops(l)))(convert(n, base, 8)):
    select(isprime, [seq(f(i), i=0..600)])[];  # Alois P. Heinz, Jul 19 2025
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 5] == 0 &]
  • PARI
    primes_with(, 1, [0, 2, 3, 4, 6, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("02346789"), 41))) # uses function/imports in A385776
    

A386332 Primes without {1, 6} as digits.

Original entry on oeis.org

2, 3, 5, 7, 23, 29, 37, 43, 47, 53, 59, 73, 79, 83, 89, 97, 223, 227, 229, 233, 239, 257, 277, 283, 293, 307, 337, 347, 349, 353, 359, 373, 379, 383, 389, 397, 409, 433, 439, 443, 449, 457, 479, 487, 499, 503, 509, 523, 547, 557, 577, 587, 593, 599, 709, 727
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038614.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 2, 3, 4, 5, 7, 8, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 6] == 0 &]
  • PARI
    primes_with(, 1, [0, 2, 3, 4, 5, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("02345789"), 41))) # uses function/imports in A385776
    

A386333 Primes without {1, 7} as digits.

Original entry on oeis.org

2, 3, 5, 23, 29, 43, 53, 59, 83, 89, 223, 229, 233, 239, 263, 269, 283, 293, 349, 353, 359, 383, 389, 409, 433, 439, 443, 449, 463, 499, 503, 509, 523, 563, 569, 593, 599, 643, 653, 659, 683, 809, 823, 829, 839, 853, 859, 863, 883, 929, 953, 983, 2003, 2029, 2039
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038615.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 2, 3, 4, 5, 6, 8, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 7] == 0 &]
  • PARI
    primes_with(, 1, [0, 2, 3, 4, 5, 6, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("02345689"), 41))) # uses function/imports in A385776
    
Previous Showing 21-30 of 31 results. Next