A057851 -id:A057851 - cp's OEIS frontend

A006450 Prime-indexed primes: primes with prime subscripts.

3, 5, 11, 17, 31, 41, 59, 67, 83, 109, 127, 157, 179, 191, 211, 241, 277, 283, 331, 353, 367, 401, 431, 461, 509, 547, 563, 587, 599, 617, 709, 739, 773, 797, 859, 877, 919, 967, 991, 1031, 1063, 1087, 1153, 1171, 1201, 1217, 1297, 1409, 1433, 1447, 1471

Offset: 1

Jeffrey Shallit, Nov 25 1975

A000040 = A006450 U A007821. - Juri-Stepan Gerasimov, Sep 24 2009
Subsequence of A175247 (primes (A000040) with noncomposite (A008578) subscripts), a(n) = A175247(n+1). - Jaroslav Krizek, Mar 13 2010
Primes p such that p and pi(p) are both primes. - Juri-Stepan Gerasimov, Jul 14 2011
Sum_{n>=1} 1/a(n) converges. In fact, Sum_{n>N} 1/a(n) < 1/log(N), by the integral test. - Jonathan Sondow, Jul 11 2012
The number of such primes not exceeding x > 0 is pi(pi(x)). I conjecture that the sequence a(n)^(1/n) (n = 1,2,3,...) is strictly decreasing. This is an analog of the Firoozbakht conjecture on primes. - Zhi-Wei Sun, Aug 17 2015
Limit_{n->infinity} a(n)/(n*(log(n))^2) = 1. Proof: By Cipolla's asymptotic formula, prime(n) ~ L(n) + R(n), where L(n)/n = log(n) + log(log(n)) - 1 and R(n)/n decreases logarithmically to 0. Hence, for large n, a(n) = prime(prime(n)) ~ L(L(n)+R(n)) + R(L(n)+R(n)) = n*(log(n))^2 + r(n), where r(n) grows as O(n*log(n)*log(log(n))). The rest of the proof is trivial. The convergence is very slow: for k = 1,2,3,4,5,6, sqrt(a(10^k)/10^k)/log(10^k) evaluates to 2.055, 1.844, 1.695, 1.611, 1.545, and 1.493, respectively. - Stanislav Sykora, Dec 09 2015

			a(5) = 31 because a(5) = p(p(5)) = p(11) = 31.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

J. S. Kimberley, Table of n, a(n) for n = 1..100000
R. G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
Jonathan Bayless, Dominic Klyve, and Tomás Oliveira e Silva, New Bounds and Computations on Prime-Indexed Primes, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 13, Paper A43, 2013.
K. A. Broughan and A. R. Barnett, On the subsequence of primes having prime subscripts, JIS 12 (2009) 09.2.3.
Paul Cooijmans, Numbers.
Paul Cooijmans, Short Test For Genius.
R. E. Dressler and S. T. Parker, Primes with a prime subscript, J. ACM 22 (1975) 380-381.
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
N. Fernandez, More terms of this and other sequences related to A049076.
A. B. Frizell, The permutations of the natural numbers can not be well ordered, Bull. Amer. Math. Soc. 22 (1915), no. 2, 71-73.
Ernest G. Hibbs, Component Interactions of the Prime Numbers, Ph. D. Thesis, Capitol Technology Univ. (2022), see p. 33.
Michael P. May, Properties of Higher-Order Prime Number Sequences, Missouri J. Math. Sci. (2020) Vol. 32, No. 2, 158-170; and arXiv version, arXiv:2108.04662 [math.NT], 2021.
Boris Putievskiy, Transformations [Of] Integer Sequences And Pairing Functions, arXiv preprint arXiv:1212.2732 [math.CO], 2012.
J. Shallit, Letter to N. J. A. Sloane, Oct. 1975
Eric Weisstein's World of Mathematics, Prime formulas, see Cipolla formula.

Primes for which A049076 > 1.
Cf. A000040, A007821, A038580, A049090, A049202, A049203, A057847, A057849, A057850, A057851, A058332, A093047.
Cf. A185723 and A214296 for numbers and primes that are sums of distinct a(n); cf. A213356 and A185724 for those that are not.
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.

a006450 = a000040 . a000040
a006450_list = map a000040 a000040_list
-- Reinhard Zumkeller, Jan 12 2013

[ NthPrime(NthPrime(n)): n in [1..51] ]; // Jason Kimberley, Apr 02 2010

seq(ithprime(ithprime(i)),i=1..50); # Uli Baum (Uli_Baum(AT)gmx.de), Sep 05 2007
# For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016

Mathematica
```
Table[ Prime[ Prime[ n ] ], {n, 100} ]
```

i=0;forprime(p=2,1e4,if(isprime(i++),print1(p", "))) \\ Charles R Greathouse IV, Jun 10 2011

a=vector(10^3,n,prime(prime(n))) \\ Stanislav Sykora, Dec 09 2015

from sympy import prime
def a(n): return prime(prime(n))
print([a(n) for n in range(1, 52)]) # Michael S. Branicky, Aug 11 2021

# much faster version for initial segment of sequence
from sympy import nextprime, isprime
def aupton(terms):
    alst, p, pi = [], 2, 1
    while len(alst) < terms:
        if isprime(pi): alst.append(p)
        p, pi = nextprime(p), pi+1
    return alst
print(aupton(10000)) # Michael S. Branicky, Aug 11 2021

a(n) = prime(prime(n)) = A000040(A000040(n)). - Juri-Stepan Gerasimov, Sep 24 2009
a(n) > n*(log(n))^2, as prime(n) > n*log(n) by Rosser's theorem. - Jonathan Sondow, Jul 11 2012
a(n)/log(a(n)) ~ prime(n). - Thomas Ordowski, Mar 30 2015
Sum_{n>=1} 1/a(n) is in the interval (1.04299, 1.04365) (Bayless et al., 2013). - Amiram Eldar, Oct 15 2020

A038580 Primes with indices that are primes with prime indices.

Original entry on oeis.org

5, 11, 31, 59, 127, 179, 277, 331, 431, 599, 709, 919, 1063, 1153, 1297, 1523, 1787, 1847, 2221, 2381, 2477, 2749, 3001, 3259, 3637, 3943, 4091, 4273, 4397, 4549, 5381, 5623, 5869, 6113, 6661, 6823, 7193, 7607, 7841, 8221, 8527, 8719, 9319, 9461, 9739

Offset: 1

Brian Galebach

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from T. D. Noe)
Robert G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
Robert E. Dressler and S. Thomas Parker, Primes with a prime subscript, J. ACM, Volume 22 Issue 3, July 1975, 380-381.
Neil Fernandez, An order of primeness, F(p).
Neil Fernandez, An order of primeness. [cached copy, included with permission of the author]
Neil Fernandez, More terms of this and other sequences related to A049076.
Michael P. May, Properties of Higher-Order Prime Number Sequences, Missouri J. Math. Sci. (2020) Vol. 32, No. 2, 158-170; and arXiv version, arXiv:2108.04662 [math.NT], 2021.

Primes p for which A049076(p) > 3.
Cf. A049090, A049202, A049203, A057847, A057849, A057850, A057851, A058332, A086749, A093047.
Second differences give A245175.
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.

[NthPrime(NthPrime(NthPrime(n))): n in [1..50]]; // Vincenzo Librandi, Jul 17 2016

a:= ithprime@@3;
seq(a(n), n=1..50);  # Alois P. Heinz, Jun 14 2015
# For Maple code for the prime/nonprime compound sequences (listed in cross-references) see A003622. - N. J. A. Sloane, Mar 30 2016

Table[ Prime[ Prime[ Prime[ n ] ] ], {n, 1, 60} ]
Nest[Prime, Range[45], 3] (* Robert G. Wilson v, Mar 15 2004 *)

a(n) = prime(prime(prime(n))) \\ Charles R Greathouse IV, Apr 28 2015

list(lim)=my(v=List(),q,r); forprime(p=2,lim, if(isprime(q++) && isprime(r++), listput(v,p))); Set(v) \\ Charles R Greathouse IV, Feb 14 2017

a(n) = prime(prime(prime(n))).

a(n) ~ n*log(n)^3. - Ilya Gutkovskiy, Jul 17 2016

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

Neil Fernandez

nonn

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

Michael De Vlieger, Table of n, a(n) for n = 1..10000 (first 1000 terms from Robert G. Wilson v)
R. G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
N. Fernandez, More terms of this and other sequences related to A049076.

Cf. A000040, A006450, A038580, A049076, A049202, A049203, A057847, A057849, A057850, A057851, A058332, A093047.

map(ithprime@@3, select(isprime, [$1..157])); # Peter Luschny, Feb 17 2014

Nest[ Prime, Range[40], 4] (* Robert G. Wilson v, Mar 15 2004 *)

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

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

Name corrected by Sean A. Irvine, Jul 18 2021

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

Neil Fernandez

nonn

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

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Robert G. Wilson v)
R. G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
N. Fernandez, An order of primeness.
N. Fernandez, An order of primeness [cached copy, included with permission of the author]
Michael P. May, Properties of Higher-Order Prime Number Sequences, Missouri J. Math. Sci. (2020) Vol. 32, No. 2, 158-170; and arXiv version, arXiv:2108.04662 [math.NT], 2021.

Cf. A000040, A006450, A038580, A049076, A049090, A049202, A057847, A057849, A057850, A057851, A058332, A093047.

map(ithprime@@4, select(isprime, [$1..137])); # Peter Luschny, Feb 17 2014

Nest[ Prime, Range[35], 5] (* Robert G. Wilson v, Mar 15 2004 *)

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

a(n) = A000040(A049090(n)). - R. J. Mathar, Jul 07 2012

a(n) ~ n (log n)^5. - Charles R Greathouse IV, Feb 16 2017

More terms from Robert G. Wilson v, Nov 10 2000

Name corrected by Sean A. Irvine, Jul 21 2021

A049202 Primes p whose order of primeness A049076(p) is >= 6.

Original entry on oeis.org

127, 709, 5381, 15299, 52711, 87803, 167449, 219613, 318211, 506683, 648391, 919913, 1128889, 1254739, 1471343, 1828669, 2269733, 2364361, 3042161, 3338989, 3509299, 4030889, 4535189, 5054303, 5823667, 6478961, 6816631

Offset: 1

Neil Fernandez

nonn

Union of A058322, A058324-A058328, A093046 etc.

Michael De Vlieger, Table of n, a(n) for n = 1..10000 (first 1000 terms from Robert G. Wilson v)
R. G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]

Cf. A049076, A000040, A006450, A038580, A049090, A049203, A057849, A057850, A057851, A057847, A058332, A093047.

map(ithprime@@4,select(isprime, [$1..137])); # Peter Luschny, Feb 17 2014

Nest[ Prime, Range[35], 6] (* Robert G. Wilson v, Mar 15 2004 *)

list(lim)=my(v=List(), q, r, s, t, u); forprime(p=2, lim, if(isprime(q++) && isprime(r++) && isprime(s++) && isprime(t++) && isprime(u++), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Feb 16 2017

More terms from Robert G. Wilson v, Nov 10 2000

Name corrected by Sean A. Irvine, Jul 21 2021

A057847 Primes p whose order of primeness A078442(p) is at least 10.

Original entry on oeis.org

648391, 9737333, 174440041, 718064159, 3657500101, 7069067389, 16123689073, 22742734291, 36294260117, 64988430769, 88362852307, 136395369829, 175650481151, 200147986693, 243504973489, 318083817907, 414507281407

Offset: 1

Robert G. Wilson v, Nov 10 2000

nonn

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (first 221 terms from Robert G. Wilson v)
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]

Cf. A078442, A000040, A006450, A038580, A049090, A049203, A049202, A057849, A057850, A057851, A058332, A093047.

Nest[ Prime, Range[35], 10] (* Robert G. Wilson v, Mar 15 2004 *)

a(n)=my(k=11);while(k--,n=prime(n));n \\ Charles R Greathouse IV, Feb 24 2017

a(n) = prime(A057851(n)). - Andrew Howroyd, Nov 17 2024

Name clarified by Andrew Howroyd, Nov 17 2024

A057849 Primes p whose order of primeness A078442(p) is at least 7.

Original entry on oeis.org

709, 5381, 52711, 167449, 648391, 1128889, 2269733, 3042161, 4535189, 7474967, 9737333, 14161729, 17624813, 19734581, 23391799, 29499439, 37139213, 38790341, 50728129, 56011909, 59053067, 68425619, 77557187, 87019979, 101146501, 113256643, 119535373, 127065427

Offset: 1

Robert G. Wilson v, Nov 10 2000

nonn

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Robert G. Wilson v)
R. G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]

Cf. A078442, A000040, A006450, A038580, A049090, A049203, A049202, A057850, A057851, A057847, A058332, A093047.

a:= ithprime@@7;
seq(a(n), n=1..30);  # Alois P. Heinz, Jun 14 2015

Nest[ Prime, Range[35], 7] (* Robert G. Wilson v, Mar 15 2004 *)

list(lim)=my(v=List(), q, r, s, t, u, vv); forprime(p=2, lim, if(isprime(q++) && isprime(r++) && isprime(s++) && isprime(t++) && isprime(u++) && isprime(vv++), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Feb 16 2017

Name clarified by Andrew Howroyd, Nov 17 2024

A057850 Primes p whose order of primeness A078442(p) is at least 8.

Original entry on oeis.org

5381, 52711, 648391, 2269733, 9737333, 17624813, 37139213, 50728129, 77557187, 131807699, 174440041, 259336153, 326851121, 368345293, 440817757, 563167303, 718064159, 751783477, 997525853, 1107276647, 1170710369, 1367161723

Offset: 1

Robert G. Wilson v, Nov 10 2000

nonn

Union of A058325-A058328, A093046 etc. - R. J. Mathar, Jul 07 2012

Robert G. Wilson v, Table of n, a(n) for n = 1..11457
R. G. Batchko, A prime fractal and global quasi-self-similar structure in the distribution of prime-indexed primes, arXiv preprint arXiv:1405.2900 [math.GM], 2014.
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]

Cf. A078442, A000040, A006450, A038580, A049090, A049203, A049202, A057849, A057851, A057847, A058332, A093047.

Nest[ Prime, Range[35], 8] (* Robert G. Wilson v, Mar 15 2004 *)

list(lim)=my(v=List(), q, r, s, t, u, vv, w); forprime(p=2, lim, if(isprime(q++) && isprime(r++) && isprime(s++) && isprime(t++) && isprime(u++) && isprime(vv++) && isprime(w++), listput(v, p))); Vec(v) \\ Charles R Greathouse IV, Feb 19 2017

a(n) = A049090(A049090(n)). - James G. Merickel, Feb 14 2010

a(n) = A000040(A057849(n)). - R. J. Mathar, Jul 07 2012

Name clarified by Andrew Howroyd, Nov 17 2024

A058332 Primes p whose order of primeness A078442(p) is at least 11.

Original entry on oeis.org

9737333, 174440041, 3657500101, 16123689073, 88362852307, 175650481151, 414507281407, 592821132889, 963726515729, 1765037224331, 2428095424619, 3809491708961, 4952019383323, 5669795882633, 6947574946087, 9163611272327

Offset: 1

Robert G. Wilson v, Dec 12 2000

nonn

Robert G. Wilson v, Table of n, a(n) for n = 1..47.
N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]

Cf. A078442, A000040, A006450, A038580, A049090, A049203, A049202, A057849, A057850, A057851, A057847, A093047.

Nest[ Prime, Range[35], 11] (* Robert G. Wilson v, Mar 15 2004 *)

a(n) = prime(A057847(n)). - Andrew Howroyd, Nov 17 2024

Name clarified by Andrew Howroyd, Nov 17 2024

A093047 Primes p whose order of primeness A078442(p) is at least 12.

Original entry on oeis.org

174440041, 3657500101, 88362852307, 414507281407, 2428095424619, 4952019383323, 12055296811267, 17461204521323, 28871271685163, 53982894593057, 75063692618249, 119543903707171, 156740126985437, 180252380737439, 222334565193649

Offset: 1

Robert G. Wilson v, Mar 15 2000

Primes p whose primeness is > 12: 3657500101, 88362852307, 2428095424619, 12055296811267, 75063692618249, 156740126985437, ..., . - Robert G. Wilson v, Mar 15 2000

N. Fernandez, An order of primeness, F(p)
N. Fernandez, An order of primeness [cached copy, included with permission of the author]

Cf. A078442, A000040, A006450, A038580, A049090, A049203, A049202, A057849, A057850, A057851, A057847, A058332, A093047.

Nest[ Prime, Range[35], 12] (* Robert G. Wilson v, Mar 15 2004 *)

a(n) = A058332(prime(n)). - Andrew Howroyd, Nov 17 2024

Name clarified by Andrew Howroyd, Nov 17 2024

cp's OEIS Frontend

A006450 Prime-indexed primes: primes with prime subscripts.

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A038580 Primes with indices that are primes with prime indices.

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A049090 Primes for which A049076 >= 4.

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

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A049202 Primes p whose order of primeness A049076(p) is >= 6.

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A057847 Primes p whose order of primeness A078442(p) is at least 10.

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