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 1-10 of 10 results.

A260381 Primes having only {3, 7, 8} as digits.

Original entry on oeis.org

3, 7, 37, 73, 83, 337, 373, 383, 733, 773, 787, 877, 883, 887, 3373, 3733, 3833, 3877, 7333, 7873, 7877, 7883, 8377, 8387, 8737, 8783, 8837, 8887, 33377, 33773, 37337, 37783, 38333, 38377, 38737, 38783, 38833, 38873, 73387, 73783, 73877, 73883, 77377, 77383
Offset: 1

Views

Author

Vincenzo Librandi, Aug 01 2015

Keywords

Comments

A020463, A020464 and A020470 are subsequences.

Links

Crossrefs

Cf. similar sequences listed in A260378.
Cf. A000040, A020463, A020464, A020470.

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [3, 7, 8]];
  • Mathematica
    Select[Prime[Range[2 10^4]], Complement[IntegerDigits[#], {3, 7, 8}]=={} &]

A260830 Primes having only {5, 7, 8} as digits.

Original entry on oeis.org

5, 7, 557, 577, 587, 757, 787, 857, 877, 887, 5557, 5857, 7577, 7757, 7877, 8887, 55787, 57557, 57587, 57787, 58757, 58787, 75557, 75577, 75787, 77557, 77587, 78577, 78787, 78857, 78877, 78887, 85577, 87557, 87587, 87877, 87887, 555557, 555857, 557857, 558587
Offset: 1

Views

Author

Vincenzo Librandi, Aug 02 2015

Keywords

Comments

A020467 and A020470 are subsequences.

Links

Crossrefs

Cf. similar sequences listed in A260827.
Cf. A020467, A020470.

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^6) | Set(Intseq(p)) subset [5,7,8]];
  • Mathematica
    Select[Prime[Range[2 10^5]], Complement[IntegerDigits[#], {5, 7, 8}] == {} &]
Select[Flatten[Table[FromDigits/@Tuples[{5,7,8},n],{n,6}]],PrimeQ] (* Harvey P. Dale, Oct 06 2017 *)

A260892 Primes having only {1, 7, 8} as digits.

Original entry on oeis.org

7, 11, 17, 71, 181, 787, 811, 877, 881, 887, 1117, 1171, 1181, 1187, 1777, 1787, 1811, 1871, 1877, 7177, 7187, 7717, 7817, 7877, 8111, 8117, 8171, 8887, 11117, 11171, 11177, 11717, 11777, 11887, 17117, 17881, 18181, 18787, 71171, 71711, 71777, 71881, 71887
Offset: 1

Views

Author

Vincenzo Librandi, Aug 07 2015

Keywords

Comments

A020455, A020456 and A020470 are subsequences.

Links

Crossrefs

Cf. similar sequences listed in A260889.
Cf. A000040, A020455, A020456, A020470.

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^5) | Set(Intseq(p)) subset [1, 7, 8]];
  • Mathematica
    Select[Prime[Range[2 10^5]], Complement[IntegerDigits[#], {1, 7, 8}] == {} &]

A385789 Primes having only {2, 7, 8} as digits.

Original entry on oeis.org

2, 7, 227, 277, 727, 787, 827, 877, 887, 2287, 2777, 2887, 7727, 7877, 8287, 8887, 22277, 22727, 22777, 22787, 22877, 27277, 27827, 28277, 72227, 72277, 72287, 72727, 78277, 78787, 78877, 78887, 82727, 82787, 87277, 87877, 87887, 222787, 222877, 227827, 228887
Offset: 1

Views

Author

Jason Bard, Jul 13 2025

Keywords

Links

Crossrefs

Supersequence of A020459, A020470.
Cf. A000040, A030432, A385776.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [2, 7, 8]];
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{2, 7, 8}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [2, 7, 8]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("278"), 41))) # uses function/imports in A385776

A385795 Primes having only {4, 7, 8} as digits.

Original entry on oeis.org

7, 47, 487, 787, 877, 887, 4447, 4787, 4877, 7477, 7487, 7877, 8447, 8747, 8887, 44777, 44887, 47777, 48487, 48787, 48847, 74747, 74887, 77447, 77477, 77747, 78487, 78787, 78877, 78887, 84787, 87877, 87887, 88747, 444487, 444877, 444887, 447877, 474787, 474847
Offset: 1

Views

Author

Jason Bard, Jul 13 2025

Keywords

Links

Crossrefs

Subsequence of A030432.
Supersequence of A020465, A020470.
Cf. A000040, A385776.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [4, 7, 8]];
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{4, 7, 8}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [4, 7, 8]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("478"), 41))) # uses function/imports in A385776

A385771 Primes having only {0, 7, 8} as digits.

Original entry on oeis.org

7, 787, 877, 887, 7877, 8087, 8707, 8807, 8887, 70877, 78007, 78707, 78787, 78877, 78887, 80077, 80777, 87877, 87887, 88007, 88807, 700087, 700877, 707887, 708007, 777787, 777877, 778777, 780707, 780877, 780887, 787777, 787807, 788077, 788087, 800077
Offset: 1

Views

Author

Jason Bard, Jul 09 2025

Keywords

Examples

			7877 is a term because it is prime and only has {0,7,8} as digits.

Links

Crossrefs

Subsequence of A030432.
Cf. A000040, A020470, A385776.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [0, 7, 8]];
  • Mathematica
    Select[FromDigits/@Tuples[{0,7,8},5],PrimeQ]
  • PARI
    primes_with(, 1, [0, 7, 8]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("078"), 41))) # uses function/imports in A385776

A385799 Primes having only {6, 7, 8} as digits.

Original entry on oeis.org

7, 67, 677, 787, 877, 887, 7687, 7867, 7877, 8677, 8867, 8887, 66877, 67777, 67867, 68687, 68767, 68777, 76667, 76777, 77687, 77867, 78787, 78877, 78887, 86677, 86767, 87767, 87877, 87887, 88667, 88867, 666667, 667687, 667867, 668677, 668687, 668867, 677687, 677767
Offset: 1

Views

Author

Jason Bard, Jul 14 2025

Keywords

Links

Crossrefs

Subsequence of A030432, A106111.
Supersequence of A020469, A020470.
Cf. A000040, A385776.

Programs

  • Magma
    [p: p in PrimesUpTo(10^6) | Set(Intseq(p)) subset [6, 7, 8]];
  • Mathematica
    Flatten[Table[Select[FromDigits /@ Tuples[{6, 7, 8}, n], PrimeQ], {n, 7}]]
  • PARI
    primes_with(, 1, [6, 7, 8]) \\ uses function in A385776
  • Python
    print(list(islice(primes_with("678"), 41))) # uses function/imports in A385776

A036323 Composite numbers whose prime factors contain no digits other than 7 and 8.

Original entry on oeis.org

49, 343, 2401, 5509, 6139, 6209, 16807, 38563, 42973, 43463, 55139, 62209, 117649, 269941, 300811, 304241, 385973, 435463, 551509, 552139, 552209, 615139, 615209, 619369, 690199, 698069, 769129, 777899, 786769, 823543, 1889587, 2105677
Offset: 1

Views

Author

Patrick De Geest, Dec 15 1998

Keywords

Comments

All terms are a product of at least two terms of A020470. - David A. Corneth, Oct 09 2020

Links

Crossrefs

Cf. A020470, A036302-A036325.

Programs

  • Mathematica
    Select[Range[25*10^5],CompositeQ[#]&&SubsetQ[{7,8},Flatten[ IntegerDigits/@ Transpose[ FactorInteger[#]][[1]]]]&] (* Harvey P. Dale, Jan 19 2015 *)

Formula

Sum_{n>=1} 1/a(n) = Product_{p in A020470} (p/(p - 1)) - Sum_{p in A020470} 1/p - 1 = 0.0244618735... . - Amiram Eldar, May 22 2022

A036949 Smallest n-digit prime containing only the digits 7 and 8, or 0 if no such prime exists.

Original entry on oeis.org

7, 0, 787, 7877, 78787, 777787, 7778777, 77778887, 777788887, 7777778887, 77777778887, 777777777877, 7777777787777, 77777777778787, 777777777777787, 7777777778788777, 77777777777778887, 777777777787878887
Offset: 1

Views

Author

Patrick De Geest, Jan 04 1999

Keywords

Links

Crossrefs

Cf. A020470, A036229, A036323.

Programs

  • Mathematica
    Table[SelectFirst[FromDigits/@Tuples[{7,8},n],PrimeQ],{n,18}]/.Missing[ "NotFound"]->0 (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Oct 07 2018 *)

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

Links

Crossrefs

Intersection of A038615 and A038616.
Cf. A000040, A020470, A385776.

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
Showing 1-10 of 10 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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