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 57 results. Next

A049078 Primes prime(k) for which A049076(k) = 2.

Original entry on oeis.org

3, 17, 41, 67, 83, 109, 157, 191, 211, 241, 283, 353, 367, 401, 461, 509, 547, 563, 587, 617, 739, 773, 797, 859, 877, 967, 991, 1031, 1087, 1171, 1201, 1217, 1409, 1433, 1447, 1471, 1499, 1597, 1621, 1669, 1723, 1741, 1823, 1913, 2027, 2063, 2081, 2099
Offset: 1

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Examples

			For these primes S(p) is a prime but S(S(p)) is not. E.g. S(17)=7, S(7)=4.
		

Crossrefs

Let A = primes A000040, B = nonprimes A018252. The 2-level compounds are AA = A006450, AB = A007821, BA = A078782, BB = A102615. The 3-level compounds AAA, AAB, ..., BBB are A038580, A049078, A270792, A102617, A270794, A270795, A270796, A102616.

Programs

Formula

a(n) = prime(A007821(n)). - Juri-Stepan Gerasimov, Aug 11 2008
a(n) ~ A006450(n) ~ n log^2 n. - Charles R Greathouse IV, Apr 29 2015

Extensions

Edited by N. J. A. Sloane, Aug 29 2008 at the suggestion of R. J. Mathar
Spelling/notation corrections by Charles R Greathouse IV, Mar 18 2010

A049081 Primes prime(k) for which A049076(k) = 5.

Original entry on oeis.org

31, 1787, 8527, 19577, 27457, 42043, 72727, 96797, 112129, 137077, 173867, 239489, 250751, 285191, 352007, 401519, 443419, 464939, 490643, 527623, 683873, 718807, 755387, 839483, 864013, 985151, 1021271, 1080923, 1159901, 1278779
Offset: 1

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Extensions

More terms from Robert G. Wilson v, Dec 12 2000

A049079 Primes prime(k) for which A049076(k) = 3.

Original entry on oeis.org

5, 59, 179, 331, 431, 599, 919, 1153, 1297, 1523, 1847, 2381, 2477, 2749, 3259, 3637, 3943, 4091, 4273, 4549, 5623, 5869, 6113, 6661, 6823, 7607, 7841, 8221, 8719, 9461, 9739, 9859, 11743, 11953, 12097, 12301, 12547, 13469, 13709, 14177, 14723, 14867
Offset: 1

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Definition edited by Zak Seidov, Sep 15 2013

A049090 Primes for which A049076 >= 4.

Original entry on oeis.org

11, 31, 127, 277, 709, 1063, 1787, 2221, 3001, 4397, 5381, 7193, 8527, 9319, 10631, 12763, 15299, 15823, 19577, 21179, 22093, 24859, 27457, 30133, 33967, 37217, 38833, 40819, 42043, 43651, 52711, 55351, 57943, 60647, 66851, 68639, 72727
Offset: 1

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Comments

Union of A049080, A049081, A058322, A058324, etc. - R. J. Mathar, Jul 07 2012

Crossrefs

Programs

  • Maple
    map(ithprime@@3, select(isprime, [$1..157])); # Peter Luschny, Feb 17 2014
  • Mathematica
    Nest[ Prime, Range[40], 4] (* Robert G. Wilson v, Mar 15 2004 *)
  • PARI
    list(lim)=my(v=List(),q,r,s); forprime(p=2,lim,if(isprime(q++)&&isprime(r++)&&isprime(s++),listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 16 2017

Formula

a(n) = A006450(A006450(n)). - James G. Merickel, Feb 14 2010
a(n) = A000040(A038580(n)). - R. J. Mathar, Jul 07 2012
a(n) ~ n (log n)^4. - Charles R Greathouse IV, Feb 16 2017

Extensions

Name corrected by Sean A. Irvine, Jul 18 2021

A058322 Primes for which A049076(p) = 7.

Original entry on oeis.org

127, 15299, 87803, 219613, 318211, 506683, 919913, 1254739, 1471343, 1828669, 2364361, 3338989, 3509299, 4030889, 5054303, 5823667, 6478961, 6816631, 7220981, 7807321, 10311439, 10875143, 11469013, 12838937, 13243033, 15239333, 15837299, 16827557, 18143603
Offset: 1

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Author

Robert G. Wilson v, Dec 12 2000

Keywords

Crossrefs

Programs

  • Maple
    A058322 := proc(n)
            ithprime(A049081(n)) ;
    end proc: # R. J. Mathar, Jul 07 2012
    # second Maple program:
    map(ithprime@@6, remove(isprime, [$1..42]))[];  # Alois P. Heinz, Mar 15 2020
  • Mathematica
    Nest[ Prime, Select[ Range[40], !PrimeQ[ # ] &], 6] (* Robert G. Wilson v, Mar 15 2004 *)

Formula

a(n) = A000040(A049081(n)).

Extensions

More terms from Alois P. Heinz, Mar 15 2020

A049080 Primes prime(k) for which A049076(k) = 4.

Original entry on oeis.org

11, 277, 1063, 2221, 3001, 4397, 7193, 9319, 10631, 12763, 15823, 21179, 22093, 24859, 30133, 33967, 37217, 38833, 40819, 43651, 55351, 57943, 60647, 66851, 68639, 77431, 80071, 84347, 90023, 98519, 101701, 103069, 125113, 127643
Offset: 1

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A049203 Primes for which A049076(p) >= 5.

Original entry on oeis.org

31, 127, 709, 1787, 5381, 8527, 15299, 19577, 27457, 42043, 52711, 72727, 87803, 96797, 112129, 137077, 167449, 173867, 219613, 239489, 250751, 285191, 318211, 352007, 401519, 443419, 464939, 490643, 506683, 527623, 648391, 683873, 718807
Offset: 1

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Comments

Union of A049081, A058322, A058324-A058328, A093046, etc. - R. J. Mathar, Jul 07 2012

Crossrefs

Programs

  • Maple
    map(ithprime@@4, select(isprime, [$1..137])); # Peter Luschny, Feb 17 2014
  • Mathematica
    Nest[ Prime, Range[35], 5] (* Robert G. Wilson v, Mar 15 2004 *)
  • PARI
    list(lim)=my(v=List(),q,r,s,t); forprime(p=2,lim, if(isprime(q++) && isprime(r++) && isprime(s++) && isprime(t++), listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 16 2017

Formula

a(n) = A000040(A049090(n)). - R. J. Mathar, Jul 07 2012
a(n) ~ n (log n)^5. - Charles R Greathouse IV, Feb 16 2017

Extensions

More terms from Robert G. Wilson v, Nov 10 2000
Name corrected by Sean A. Irvine, Jul 21 2021

A058324 Primes for which A049076(p) = 8.

Original entry on oeis.org

709, 167449, 1128889, 3042161, 4535189, 7474967, 14161729, 19734581, 23391799, 29499439, 38790341, 56011909, 59053067, 68425619, 87019979, 101146501, 113256643, 119535373, 127065427, 138034009, 185350441, 196100297, 207460717, 233784751, 241568891, 280256489
Offset: 1

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Author

Robert G. Wilson v, Dec 12 2000

Keywords

Crossrefs

Programs

  • Maple
    map(ithprime@@7, remove(isprime, [$1..38]))[];  # Alois P. Heinz, Mar 15 2020
  • Mathematica
    Nest[ Prime, Select[ Range[34], !PrimeQ[ # ] &], 7] (* Robert G. Wilson v, Mar 15 2004 *)

Formula

a(n) = A000040(A058322(n)). - R. J. Mathar, Jul 07 2012

Extensions

More terms from Alois P. Heinz, Mar 15 2020

A058328 Primes for which A049076(p) = 12.

Original entry on oeis.org

9737333, 16123689073, 175650481151, 592821132889, 963726515729, 1765037224331, 3809491708961, 5669795882633, 6947574946087, 9163611272327, 12695664159413, 19638537755027, 20909033866927, 24894639811901
Offset: 1

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Author

Robert G. Wilson v, Dec 12 2000

Keywords

Crossrefs

Programs

  • Mathematica
    Nest[ Prime, Select[ Range[30], !PrimeQ[ # ] &], 11] (* Robert G. Wilson v, Mar 15 2004 *)

Formula

a(n) = A000040(A058327(n)). - R. J. Mathar, Jul 07 2012

A093046 Primes for which A049076(p) = 13.

Original entry on oeis.org

174440041, 414507281407, 4952019383323, 17461204521323, 28871271685163, 53982894593057, 119543903707171, 180252380737439, 222334565193649, 295872998567819, 414190707114539, 649544694886663, 692919372869953, 829484152743469, 1111923751842437, 1335294947809661, 1532021237514419, 1635795965187779
Offset: 1

Views

Author

Robert G. Wilson v, Mar 15 2000

Keywords

Crossrefs

Programs

  • Mathematica
    Nest[ Prime, Select[ Range[30], !PrimeQ[ # ] &], 12]

Formula

a(n) = A000040(A058328(n)). - R. J. Mathar, Jul 07 2012

Extensions

a(7)-a(9) from Robert G. Wilson v, Dec 27 2005
a(10)-a(18) from Robert G. Wilson v, Mar 08 2017 using Kim Walisch's primecount.
Showing 1-10 of 57 results. Next