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 1-6 of 6 results.

A178550 Primes with exactly one digit 1.

Original entry on oeis.org

13, 17, 19, 31, 41, 61, 71, 103, 107, 109, 127, 137, 139, 149, 157, 163, 167, 173, 179, 193, 197, 199, 241, 251, 271, 281, 313, 317, 331, 401, 419, 421, 431, 461, 491, 521, 541, 571, 601, 613, 617, 619, 631, 641, 661, 691, 701, 719, 751, 761, 821, 881, 919, 941, 971, 991
Offset: 1

Views

Author

Lekraj Beedassy, May 29 2010

Keywords

Links

Crossrefs

Intersection of A043493 and A000040.
Cf. A038618, A178551, A178552, A178553, A178554, A178555, A178556, A178557, A178558.

Programs

  • Mathematica
    Select[Prime[Range[200]],Count[IntegerDigits[#],1]==1 &] (* Stefano Spezia, Aug 29 2025 *)
  • Python
    from sympy import isprime
print([i for i in range(1000) if str(i).count('1') == 1 and isprime(i)]) # Daniel Starodubtsev, Mar 29 2020

Formula

a(n) >> n^k where k = log(10)/log(9) = 1.04795.... - Charles R Greathouse IV, Jan 21 2025

A178558 Primes with exactly nine 9's.

Original entry on oeis.org

9199999999, 9299999999, 9959999999, 9995999999, 9999499999, 9999929999, 9999959999, 9999999929, 10999999999, 16999999999, 19399999999, 19909999999, 19991999999, 19999399999, 19999990999, 19999997999, 19999999199
Offset: 1

Views

Author

Lekraj Beedassy, May 29 2010

Keywords

Crossrefs

Cf. A038618, A178550-A178557

A178551 Primes with exactly two 2's.

Original entry on oeis.org

223, 227, 229, 1223, 1229, 2027, 2029, 2129, 2203, 2207, 2213, 2237, 2239, 2243, 2251, 2267, 2269, 2273, 2281, 2287, 2293, 2297, 2423, 2521, 2621, 2729, 2927, 3221, 3229, 4229, 5227, 6221, 6229, 7229, 8221, 9221, 9227, 10223, 12203, 12211, 12239, 12241, 12251, 12253
Offset: 1

Views

Author

Lekraj Beedassy, May 29 2010

Keywords

Links

Crossrefs

Cf. A038618, A178550, A178552, A178553, A178554, A178555, A178556, A178557, A178558.

Programs

  • Mathematica
    Select[Prime[Range[1500]],Count[IntegerDigits[#],2]==2 &] (* Stefano Spezia, Aug 29 2025 *)
  • Python
    from sympy import isprime
print([i for i in range(10000) if str(i).count('2') == 2 and isprime(i)]) # Daniel Starodubtsev, Mar 29 2020

A178553 Primes with exactly four 4's.

Original entry on oeis.org

44449, 404449, 440441, 440443, 441443, 441449, 442447, 444043, 444047, 444341, 444343, 444347, 444349, 444401, 444403, 444421, 444461, 444463, 444469, 444473, 444487, 444547, 444641, 444649, 444841, 445447, 446441, 446447, 447443, 447449, 449441
Offset: 1

Views

Author

Lekraj Beedassy, May 29 2010

Keywords

Links

Crossrefs

Cf. A038618, A178550, A178551, A178552, A178554, A178555, A178556, A178557, A178558.

Programs

  • PARI
    isok(p) = isprime(p) && (#select(x->(x==4), digits(p)) == 4); \\ Michel Marcus, Mar 15 2020

Extensions

Missing a(13) = 444349 inserted by Daniel Starodubtsev, Mar 15 2020

A178554 Primes with exactly five 5's.

Original entry on oeis.org

555557, 1555553, 2555551, 3555551, 3555557, 4555559, 5055551, 5055559, 5355551, 5505551, 5535559, 5550553, 5550557, 5554553, 5555057, 5555059, 5555357, 5555507, 5555509, 5555527, 5555567, 5555591, 5555653, 5556557, 5556559, 5557553
Offset: 1

Views

Author

Lekraj Beedassy, May 29 2010

Keywords

Links

Crossrefs

Cf. A038618, A178550, A178551, A178552, A178553, A178555, A178556, A178557, A178558.

Programs

  • Mathematica
    Select[Prime[Range[PrimePi[55555],1000000]],Count[IntegerDigits[#],5]==5&]  (* Harvey P. Dale, Dec 20 2010 *)
  • PARI
    isok(p) = isprime(p) && (#select(x->(x==5), digits(p)) == 5); \\ Michel Marcus, Mar 15 2020

Extensions

Missing a(14) = 5554553 inserted by Daniel Starodubtsev, Mar 15 2020

A178556 Primes with exactly seven 7's.

Original entry on oeis.org

77767777, 77777177, 77777377, 77777747, 137777777, 172777777, 177677777, 177776777, 177777377, 177777577, 177777727, 177777773, 177777779, 177797777, 197777777, 272777777, 277177777, 277727777, 277771777, 277775777, 277777177
Offset: 1

Views

Author

Lekraj Beedassy, May 29 2010

Keywords

Crossrefs

Cf. A038618, A178550-5, A178557-8

Programs

  • Mathematica
    Select[Prime[Range[45*10^5,152*10^5]],DigitCount[#,10,7]==7&] (* Harvey P. Dale, Dec 20 2022 *)
Showing 1-6 of 6 results.

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