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 1-9 of 9 results.

A261181 Primes that contain only the digits (0, 7, 9).

Original entry on oeis.org

7, 79, 97, 709, 797, 907, 977, 997, 7079, 7907, 9007, 9907, 70009, 70079, 70099, 70709, 70979, 70997, 70999, 77797, 77977, 77999, 79777, 79907, 79979, 79997, 79999, 90007, 90709, 90907, 90977, 90997, 97007, 97777, 99079, 99707, 99709, 99907, 700079
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2015

Keywords

Comments

A020471 is a subsequence.

Crossrefs

Cf. Primes that contain only the digits (k,7,9): this sequence (k=0), A260893 (k=1), A261182 (k=2), A260382 (k=3), A261183 (k=4), A260831 (k=5), A261184 (k=6), A106110 (k=8).

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [0, 7, 9]];
  • Mathematica
    Select[Prime[Range[6 10^4]], Complement[IntegerDigits[#], {0, 7, 9}] == {} &]
    Select[FromDigits/@Tuples[{0,7,9},6],PrimeQ] (* Harvey P. Dale, Aug 09 2024 *)

A106112 Primes with minimal digit > 4.

Original entry on oeis.org

5, 7, 59, 67, 79, 89, 97, 557, 569, 577, 587, 599, 659, 677, 757, 769, 787, 797, 857, 859, 877, 887, 967, 977, 997, 5557, 5569, 5657, 5659, 5669, 5689, 5779, 5857, 5867, 5869, 5879, 5897, 5987, 6569, 6577, 6599, 6659, 6679, 6689, 6779, 6857, 6869, 6899, 6959
Offset: 1

Views

Author

Zak Seidov, May 07 2005

Keywords

Crossrefs

Cf. A036956 (primes with maximal digit <= 4).

Programs

  • Mathematica
    Select[Prime[Range[1000]], Min[IntegerDigits[ # ]]>4&]

A154523 Numbers k such that the smallest decimal digit of k equals the smallest decimal digit of prime(k).

Original entry on oeis.org

11, 13, 18, 31, 41, 52, 62, 73, 80, 81, 110, 112, 113, 114, 115, 116, 121, 125, 128, 133, 135, 140, 141, 142, 152, 156, 157, 164, 167, 170, 180, 187, 188, 189, 191, 192, 193, 194, 195, 196, 198, 199, 211, 215, 216, 217, 218, 219, 221, 231, 241, 251, 261, 271
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Jan 11 2009

Keywords

Comments

Natural density 1, since almost all numbers and almost all primes (thanks to the prime number theorem) contain the digit 0.
The first terms with smallest digit 1, 2, and 3 are listed in the Data section. The first with smallest digits 4, 5, and 6 are 644, 758, and 6666, respectively. While there are plenty of primes with no decimal digit smaller than 7 (see A106110), including many primes consisting only of the digits 8 and 9 (the 10th of which is prime(77777) = 989999; cf. A020472), it seems to me that finding a term in this sequence whose smallest digit is 7 or 8 should be a very difficult problem. - Jon E. Schoenfield, Feb 11 2019

Examples

			11 is a term because prime(11) =  31 (smallest digits: 1);
13 is a term because prime(13) =  41 (smallest digits: 1);
18 is a term because prime(18) =  61 (smallest digits: 1);
31 is a term because prime(31) = 127 (smallest digits: 1);
41 is a term because prime(41) = 179 (smallest digits: 1);
52 is a term because prime(52) = 239 (smallest digits: 2).
		

Crossrefs

Programs

  • Maple
    A054054 := proc(n) min(op(convert(n,base,10)) ) ; end proc:
    for n from 1 to 500 do if A054054(n) = A054054(ithprime(n)) then printf("%d,",n ) ; end if; end do: (End) # R. J. Mathar, May 05 2010
  • Mathematica
    Transpose[Select[Table[{n,Prime[n]},{n,300}],Min[IntegerDigits[#[[1]]]] == Min[IntegerDigits[#[[2]]]]&]][[1]] (* Harvey P. Dale, Dec 18 2012 *)

Extensions

Corrected (221 inserted) by R. J. Mathar, May 05 2010
Definition clarified by Harvey P. Dale, Dec 18 2012

A386084 Primes having only {0, 7, 8, 9} as digits.

Original entry on oeis.org

7, 79, 89, 97, 709, 787, 797, 809, 877, 887, 907, 977, 997, 7079, 7789, 7877, 7879, 7907, 8009, 8087, 8089, 8707, 8779, 8807, 8887, 8999, 9007, 9787, 9887, 9907, 70009, 70079, 70099, 70709, 70877, 70879, 70979, 70997, 70999, 77797, 77899, 77977, 77999, 78007
Offset: 1

Views

Author

Jason Bard, Jul 16 2025

Keywords

Crossrefs

Supersequence of A106110, A261181, A385771, A385772.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 7, 8, 9]];
    
  • Mathematica
    Select[FromDigits /@ Tuples[{0, 7, 8, 9}, n], PrimeQ]
  • PARI
    primes_with(, 1, [0, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("0789"), 41))) # uses function/imports in A385776
    

A386138 Primes having only {1, 7, 8, 9} as digits.

Original entry on oeis.org

7, 11, 17, 19, 71, 79, 89, 97, 179, 181, 191, 197, 199, 719, 787, 797, 811, 877, 881, 887, 911, 919, 971, 977, 991, 997, 1117, 1171, 1181, 1187, 1777, 1787, 1789, 1811, 1871, 1877, 1879, 1889, 1979, 1987, 1997, 1999, 7177, 7187, 7717, 7789, 7817, 7877, 7879, 7919
Offset: 1

Views

Author

Jason Bard, Jul 17 2025

Keywords

Crossrefs

Supersequence of A106110, A260892, A260893, A385783.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [1, 7, 8, 9]];
    
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{1, 7, 8, 9}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [1, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("1789"), 41))) # uses function/imports in A385776
    

A386168 Primes having only {2, 7, 8, 9} as digits.

Original entry on oeis.org

2, 7, 29, 79, 89, 97, 227, 229, 277, 727, 787, 797, 827, 829, 877, 887, 929, 977, 997, 2287, 2297, 2729, 2777, 2789, 2797, 2879, 2887, 2897, 2927, 2999, 7229, 7297, 7727, 7789, 7829, 7877, 7879, 7927, 8287, 8297, 8779, 8887, 8929, 8999, 9227, 9277, 9787, 9829
Offset: 1

Views

Author

Jason Bard, Jul 18 2025

Keywords

Crossrefs

Supersequence of A106110, A261182, A385789, A385790.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [2, 7, 8, 9]];
    
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{2, 7, 8, 9}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [2, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("2789"), 41))) # uses function/imports in A385776
    

A386187 Primes having only {3, 7, 8, 9} as digits.

Original entry on oeis.org

3, 7, 37, 73, 79, 83, 89, 97, 337, 373, 379, 383, 389, 397, 733, 739, 773, 787, 797, 839, 877, 883, 887, 937, 977, 983, 997, 3373, 3389, 3733, 3739, 3779, 3793, 3797, 3833, 3877, 3889, 3989, 7333, 7393, 7789, 7793, 7873, 7877, 7879, 7883, 7933, 7937, 7993, 8377
Offset: 1

Views

Author

Jason Bard, Jul 18 2025

Keywords

Crossrefs

Supersequence of A106110, A260381, A260382, A385792.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [3, 7, 8, 9]];
    
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{3, 7, 8, 9}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [3, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("3789"), 41))) # uses function/imports in A385776
    

A386195 Primes having only {4, 7, 8, 9} as digits.

Original entry on oeis.org

7, 47, 79, 89, 97, 449, 479, 487, 499, 787, 797, 877, 887, 947, 977, 997, 4447, 4787, 4789, 4799, 4877, 4889, 4987, 4999, 7477, 7487, 7489, 7499, 7789, 7877, 7879, 7949, 8447, 8747, 8779, 8849, 8887, 8999, 9479, 9497, 9749, 9787, 9887, 9949, 44449, 44497, 44777
Offset: 1

Views

Author

Jason Bard, Jul 18 2025

Keywords

Crossrefs

Supersequence of A106110, A261183, A385795, A385796.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [4, 7, 8, 9]];
    
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{4, 7, 8, 9}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [4, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("4789"), 41))) # uses function/imports in A385776
    

A386199 Primes having only {5, 7, 8, 9} as digits.

Original entry on oeis.org

5, 7, 59, 79, 89, 97, 557, 577, 587, 599, 757, 787, 797, 857, 859, 877, 887, 977, 997, 5557, 5779, 5857, 5879, 5897, 5987, 7559, 7577, 7589, 7757, 7759, 7789, 7877, 7879, 8597, 8599, 8779, 8887, 8999, 9587, 9787, 9857, 9859, 9887, 55579, 55589, 55787, 55799, 55889
Offset: 1

Views

Author

Jason Bard, Jul 18 2025

Keywords

Crossrefs

Supersequence of A106110, A260830, A260831, A385798.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [5, 7, 8, 9]];
    
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{5, 7, 8, 9}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [5, 7, 8, 9]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("5789"), 41))) # uses function/imports in A385776
    
Showing 1-9 of 9 results.