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.

Previous Showing 11-19 of 19 results.

A254315 Number of distinct digits in the prime factorization of n (counting terms of the form p^1 as p).

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 1, 2, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 3, 2, 2, 3, 2, 2, 3, 2, 2, 3, 3, 2, 2, 2, 3, 3, 2, 2, 3, 2, 3, 3, 2, 3, 3, 2, 3, 2, 3, 2, 2, 2, 3, 3, 3, 2, 3, 2, 3, 2, 3, 2, 3, 3, 3, 3, 3
Offset: 2

Views

Author

Michel Lagneau, Jan 28 2015

Keywords

Comments

Write n as product of primes raised to powers; then a(n) is the total number of distinct digits in product representation (number of distinct digits in all the primes and number of distinct digits in all the exponents that are greater than 1).
a(n)<=10. The least n such that a(n)=10 is n = 41701690 = 2*5*47*83*1069.
Property: a(p) = A043537(p), for p prime.
From Michel Marcus, Feb 21 2015: (Start)
For p in A038604, a(p^2) = A043537(p) + 1.
For p in A038611, a(p^3) = A043537(p) + 1.
For p in A038612, a(p^4) = A043537(p) + 1.
For p in A038613, a(p^5) = A043537(p) + 1.
For p in A038614, a(p^6) = A043537(p) + 1.
For p in A038615, a(p^7) = A043537(p) + 1.
For p in A038616, a(p^8) = A043537(p) + 1.
For p in A038617, a(p^9) = A043537(p) + 1.
(End)

Examples

			a(36)=2 because 36 = 2^2 * 3^2 => 2 distinct digits.
a(414)=2 because 414 = 2 * 3^2 * 23 => 2 distinct digits.
		

Crossrefs

Programs

  • Maple
    with(ListTools):
    nn:=100:
      for n from 2 to nn do:
        n0:=length(n):lst:={}:x0:=ifactors(n):
        y:=Flatten(x0[2]):z:=convert(y,set):
        z1:=z minus {1}:nn0:=nops(z1):
         for k from 1 to nn0 do :
          t1:=convert(z1[k],base,10):z2:=convert(t1,set):
          lst:=lst union z2:
         od:
         nn1:=nops(lst):printf(`%d, `,nn1):
         od :
  • Mathematica
    f[n_] := Block[{pf = FactorInteger@ n, i}, Length@ DeleteDuplicates@ Flatten@ IntegerDigits@ Rest@ Flatten@ Reap@ Do[If[Last[pf[[i]]] == 1, Sow@ First@ pf[[i]], Sow@ FromDigits@ Flatten[IntegerDigits /@ pf[[i]]]], {i, Length@ pf}]]; Array[f,100] (* Michael De Vlieger, Jan 29 2015 *)
  • PARI
    print1(1,", ");for(k=2,100,s=[];F=factor(k);for(i=1,#F[,1],s=concat(s,digits(F[i,1]));if(F[i,2]>1,s=concat(s,digits(F[i,2]))));print1(#vecsort(s,,8),", ")) \\ Derek Orr, Jan 30 2015
    
  • Python
    from sympy import factorint
    def A254315(n):
        return len(set([x for l in [[d for d in str(p)]+[d for d in str(e) if d != '1'] for p,e in factorint(n).items()] for x in l]))
    # Chai Wah Wu, Feb 24 2015

A386326 Primes without {0, 8} as digits.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 97, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 293, 311, 313, 317, 331, 337
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038616 and A038618.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [1, 2, 3, 4, 5, 6, 7, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 0] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [1, 2, 3, 4, 5, 6, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("12345679"), 41))) # uses function/imports in A385776
    

A386334 Primes without {1, 8} as digits.

Original entry on oeis.org

2, 3, 5, 7, 23, 29, 37, 43, 47, 53, 59, 67, 73, 79, 97, 223, 227, 229, 233, 239, 257, 263, 269, 277, 293, 307, 337, 347, 349, 353, 359, 367, 373, 379, 397, 409, 433, 439, 443, 449, 457, 463, 467, 479, 499, 503, 509, 523, 547, 557, 563, 569, 577, 593, 599, 607
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038603 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 2, 3, 4, 5, 6, 7, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 1] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 2, 3, 4, 5, 6, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("02345679"), 41))) # uses function/imports in A385776
    

A386338 Primes without {2, 8} as digits.

Original entry on oeis.org

3, 5, 7, 11, 13, 17, 19, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 97, 101, 103, 107, 109, 113, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 191, 193, 197, 199, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 397, 401, 409, 419, 431
Offset: 1

Views

Author

Jason Bard, Jul 19 2025

Keywords

Crossrefs

Intersection of A038604 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 1, 3, 4, 5, 6, 7, 9]];
    
  • Maple
    f:= n-> (l-> add([0, 1, $3..7, 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, 2] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 1, 3, 4, 5, 6, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("01345679"), 41))) # uses function/imports in A385776
    

A386343 Primes without {3, 8} as digits.

Original entry on oeis.org

2, 5, 7, 11, 17, 19, 29, 41, 47, 59, 61, 67, 71, 79, 97, 101, 107, 109, 127, 149, 151, 157, 167, 179, 191, 197, 199, 211, 227, 229, 241, 251, 257, 269, 271, 277, 401, 409, 419, 421, 449, 457, 461, 467, 479, 491, 499, 509, 521, 541, 547, 557, 569, 571, 577, 599
Offset: 1

Views

Author

Jason Bard, Jul 20 2025

Keywords

Crossrefs

Intersection of A038611 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 1, 2, 4, 5, 6, 7, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 3] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 1, 2, 4, 5, 6, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("01245679"), 41))) # uses function/imports in A385776
    

A386348 Primes without {4, 8} as digits.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 53, 59, 61, 67, 71, 73, 79, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 151, 157, 163, 167, 173, 179, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 251, 257, 263, 269, 271, 277, 293, 307, 311, 313, 317, 331
Offset: 1

Views

Author

Jason Bard, Jul 20 2025

Keywords

Crossrefs

Intersection of A038612 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 1, 2, 3, 5, 6, 7, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 4] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 1, 2, 3, 5, 6, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("01235679"), 41))) # uses function/imports in A385776
    

A386352 Primes without {5, 8} as digits.

Original entry on oeis.org

2, 3, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 61, 67, 71, 73, 79, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 163, 167, 173, 179, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 263, 269, 271, 277, 293, 307, 311, 313, 317, 331, 337, 347
Offset: 1

Views

Author

Jason Bard, Jul 20 2025

Keywords

Crossrefs

Intersection of A038613 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 1, 2, 3, 4, 6, 7, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 5] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 1, 2, 3, 4, 6, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("01234679"), 41))) # uses function/imports in A385776
    

A386355 Primes without {6, 8} as digits.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 71, 73, 79, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 173, 179, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 271, 277, 293, 307, 311, 313, 317, 331, 337
Offset: 1

Views

Author

Jason Bard, Jul 20 2025

Keywords

Crossrefs

Intersection of A038614 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 1, 2, 3, 4, 5, 7, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 6] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 1, 2, 3, 4, 5, 7, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("01234579"), 41))) # uses function/imports in A385776
    

A386357 Primes without {7, 8} as digits.

Original entry on oeis.org

2, 3, 5, 11, 13, 19, 23, 29, 31, 41, 43, 53, 59, 61, 101, 103, 109, 113, 131, 139, 149, 151, 163, 191, 193, 199, 211, 223, 229, 233, 239, 241, 251, 263, 269, 293, 311, 313, 331, 349, 353, 359, 401, 409, 419, 421, 431, 433, 439, 443, 449, 461, 463, 491, 499, 503
Offset: 1

Views

Author

Jason Bard, Jul 20 2025

Keywords

Crossrefs

Intersection of A038615 and A038616.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 1, 2, 3, 4, 5, 6, 9]];
    
  • Mathematica
    Select[Prime[Range[120]], DigitCount[#, 10, 7] == 0 && DigitCount[#, 10, 8] == 0 &]
  • PARI
    primes_with(, 1, [0, 1, 2, 3, 4, 5, 6, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("01234569"), 41))) # uses function/imports in A385776
    
Previous Showing 11-19 of 19 results.