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 15 results. Next

A057196 Numbers k such that 2^k + 9 is prime.

Original entry on oeis.org

1, 2, 3, 5, 6, 7, 9, 10, 18, 23, 30, 37, 47, 57, 66, 82, 95, 119, 175, 263, 295, 317, 319, 327, 670, 697, 886, 1342, 1717, 1855, 2394, 2710, 3229, 3253, 3749, 4375, 4494, 4557, 5278, 5567, 9327, 10129, 12727, 13615, 14893, 16473, 23639, 40053, 44399, 50335, 80949
Offset: 1

Views

Author

Robert G. Wilson v, Sep 15 2000

Keywords

Comments

Some of the larger terms are only probable primes.
For these numbers k, 2^(k-1)*(2^k+9) has deficiency 10 (see A101223). - M. F. Hasler, Jul 18 2016
The terms a(48)-a(51) were found by Mike Oakes, a(52) found by Gary Barnes, and a(53-56) found by Lelio R Paula (see link Henri Lifchitz and Renaud Lifchitz). - Elmo R. Oliveira, Dec 01 2023

Examples

			For k = 10, 2^10 + 9 = 1033 is prime.
For k = 30, 2^30 + 9 = 1073741833 is prime.
		

Crossrefs

Cf. A094076, A101223, A104070 (primes of the form 2^k+9). [Klaus Brockhaus, Mar 14 2009]
Cf. A019434 (primes 2^k+1), A057732 (2^k+3), A059242 (2^k+5), A057195 (2^k+7), this sequence (2^k+9), A102633 (2^k+11), A102634 (2^k+13), A057197 (2^k+15), A057200 (2^k+17), A057221 (2^k+19), A057201 (2^k+21), A057203 (2^k+23). [M. F. Hasler, Jul 18 2016]

Programs

  • Mathematica
    Do[ If[ PrimeQ[ 2^n +9 ], Print[n]], { n, 1, 15000 }]
  • PARI
    for(n=1, oo, ispseudoprime(2^n+9)&&print1(n", ")) \\ M. F. Hasler, Jul 18 2016

Extensions

a(48)-a(51) from Mike Oakes, Aug 17 2001
Edited by T. D. Noe, Oct 30 2008

A228034 Primes of the form 9^n + 2.

Original entry on oeis.org

3, 11, 83, 6563, 59051, 4782971, 282429536483, 2541865828331, 150094635296999123, 57264168970223481226273458862846808078011946891, 30432527221704537086371993251530170531786747066637051
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2013

Keywords

Crossrefs

Cf. A004051 (primes of the form 2^a+3^b), A057735 (primes of the form 3^n+2), A090649 (associated n), A104070 (primes of the form 2^n+9), A159352 (primes of the form 10^n+3), A176495 (primes of the form 27^n+2), A182330 (primes of the form 5^n+2).

Programs

  • Magma
    [a: n in [0..300] | IsPrime(a) where a is 9^n+2];
  • Mathematica
    Select[Table[9^n + 2, {n, 0, 300}], PrimeQ]

A145440 Primes of the form 8^k + 9.

Original entry on oeis.org

17, 73, 521, 262153, 1073741833, 144115188075855881, 73786976294838206473, 273406340597876490546562778389702670669146178861651554553221325801244124899921990402939147127881737
Offset: 1

Views

Author

Vincenzo Librandi, Mar 11 2009

Keywords

Comments

8^k + 9 is prime for k = 1, 2, 3, 6, 10, 19, 22, ...

Examples

			For k=1, 8^1 + 9 =  17;
for n=2, 8^2 + 9 =  73;
for n=3, 8^3 + 9 = 521.
		

Crossrefs

A subsequence of A104070. Cf. A057196.

Programs

  • Magma
    [a: n in [0..200] | IsPrime(a) where a is 8^n+9];
  • Mathematica
    Select[8^Range[120]+9,PrimeQ]  (* Harvey P. Dale, Jan 18 2011 *)

A188165 a(n) = 2^n + 9.

Original entry on oeis.org

10, 11, 13, 17, 25, 41, 73, 137, 265, 521, 1033, 2057, 4105, 8201, 16393, 32777, 65545, 131081, 262153, 524297, 1048585, 2097161, 4194313, 8388617, 16777225, 33554441, 67108873, 134217737, 268435465, 536870921, 1073741833, 2147483657, 4294967305
Offset: 0

Views

Author

Brad Clardy, Mar 23 2011

Keywords

Crossrefs

Cf. A000079, A104070 (primes of this form), A168415.

Programs

  • Magma
    [2^n+9: n in [0..40]]; // Vincenzo Librandi, May 13 2014
  • Mathematica
    Table[2^n + 9, {n, 0, 40}] (* or *) CoefficientList[Series[(10 - 19 x)/((1 - x) (1 - 2 x)), {x, 0, 30}], x] (* Vincenzo Librandi, May 13 2014 *)
  • PARI
    a(n) = 1<Michel Marcus, Jul 19 2013
    

Formula

From Bruno Berselli, Sep 26 2011: (Start)
G.f.: (10-19*x)/(1-3*x+2*x^2).
a(n) = 2*a(n-1)-9 = 3*a(n-1)-2*a(n-2).
a(n) = A168415(n)+2. (End)
E.g.f.: exp(2*x) + 9*exp(x). - Elmo R. Oliveira, Nov 08 2023

A228026 Primes of the form 4^k + 3.

Original entry on oeis.org

7, 19, 67, 4099, 65539, 262147, 268435459, 1073741827, 19342813113834066795298819
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2013

Keywords

Examples

			67 is a term because 4^3 + 3 = 67 is prime.
		

Crossrefs

Cf. A089437 (associated k).
Cf. Primes of the form r^k + h: A092506 (r=2, h=1), A057733 (r=2, h=3), A123250 (r=2, h=5), A104066 (r=2, h=7), A104070 (r=2, h=9), A057735 (r=3, h=2), A102903 (r=3, h=4), A102870 (r=3, h=8), A102907 (r=3, h=10), A290200 (r=4, h=1), this sequence (r=4, h=3), A228027 (r=4, h=9), A182330 (r=5, h=2), A228029 (r=5, h=6), A102910 (r=5, h=8), A182331 (r=6, h=1), A104118 (r=6, h=5), A104115 (r=6, h=7), A104065 (r=7, h=4), A228030 (r=7, h=6), A228031 (r=7, h=10), A228032 (r=8, h=3), A228033 (r=8, h=5), A144360 (r=8, h=7), A145440 (r=8, h=9), A228034 (r=9, h=2), A159352 (r=10, h=3), A159031 (r=10, h=7).

Programs

  • Magma
    [a: n in [0..200] | IsPrime(a) where a is  4^n+3];
  • Mathematica
    Select[Table[4^n + 3, {n, 0, 200}], PrimeQ]

Formula

a(n) = 4^A089437(n) + 3. - Elmo R. Oliveira, Nov 14 2023

Extensions

Cross-references corrected by Robert Price, Aug 01 2017

A228032 Primes of the form 8^n + 3.

Original entry on oeis.org

11, 67, 4099, 32771, 262147, 1073741827, 19342813113834066795298819
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2013

Keywords

Crossrefs

Cf. A217354 (associated n).
Cf. Primes of the form k^n + h: A092506 (k=2, h=1), A057733 (k=2, h=3), A123250 (k=2, h=5), A104066 (k=2, h=7), A104070 (k=2, h=9), A057735 (k=3, h=2), A102903 (k=3, h=4), A102870 (k=3, h=8), A102907 (k=3, h=10), A290200 (k=4, h=1), A182330 (k=5, h=2), A102910 (k=5, h=8), A182331 (k=6, h=1), A104118 (k=6, h=5), A104115 (k=6, h=7), A104065 (k=7, h=4), this sequence (k=8, h=3), A144360 (k=8, h=7), A145440 (k=8, h=9), A228034 (k=9, h=2), A159352 (k=10, h=3), A159031 (k=10, h=7).

Programs

  • Magma
    [a: n in [0..300] | IsPrime(a) where a is  8^n+3];
  • Mathematica
    Select[Table[8^n + 3, {n, 0, 300}], PrimeQ]

Extensions

Corrected cross-references - Robert Price, Aug 01 2017

A243429 Primes of the form 2^n + 39.

Original entry on oeis.org

41, 43, 47, 71, 103, 167, 1063, 2087, 8231, 131111, 536870951, 8589934631, 549755813927, 8796093022247, 154742504910672534362390567, 40564819207303340847894502572071, 162259276829213363391578010288167, 2722258935367507707706996859454145691687
Offset: 1

Views

Author

Vincenzo Librandi, Jun 05 2014

Keywords

Comments

Associated n: 1, 2, 3, 5, 6, 7, 10, 11, 13, 17, 29, 33, 39, 43, 87, 105, 107, 131, 253, 329, ....

Crossrefs

Cf. primes of the form 2^n+k: A092506 (k=1), A057733 (k=3), A123250 (k=5), A104066 (k=7), A104070 (k=9), A156940 (k=11), A104067 (k=13), A144487 (k=15), A156973 (k=17), A104068 (k=19), A156983 (k=21), A176922 (k=23), A104072 (k=25), A104071 (k=27), A156974 (k=29), A104069 (k=31), A176926 (k=33), A176927 (k=35), A176924 (k=37), this sequence (k=39), A176925 (k=41), A243430 (k=43), A243431 (k=45), A243432 (k=47), A104073 (k=49).

Programs

  • Magma
    [a: n in [0..500] | IsPrime(a) where a is 2^n+39];
  • Mathematica
    Select[Table[2^n + 39, {n, 0, 500}], PrimeQ]

A228029 Primes of the form 5^n + 6.

Original entry on oeis.org

7, 11, 31, 131, 631, 1220703131
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2013

Keywords

Crossrefs

Cf. A089142 (associated n).
Cf. Primes of the form k^n + h: A092506 (k=2, h=1), A057733 (k=2, h=3), A123250 (k=2, h=5), A104066 (k=2, h=7), A104070 (k=2, h=9), A057735 (k=3, h=2), A102903 (k=3, h=4), A102870 (k=3, h=8), A102907 (k=3, h=10), A290200 (k=4, h=1), A182330 (k=5, h=2), this sequence (k=5, h=6), A102910 (k=5, h=8), A182331 (k=6, h=1), A104118 (k=6, h=5), A104115 (k=6, h=7), A104065 (k=7, h=4), A144360 (k=8, h=7), A145440 (k=8, h=9), A228034 (k=9, h=2), A159352 (k=10, h=3), A159031 (k=10, h=7).

Programs

  • Magma
    [a: n in [0..200] | IsPrime(a) where a is  5^n+6];
  • Mathematica
    Select[Table[5^n + 6, {n, 0, 200}], PrimeQ]

Extensions

Corrected cross-references - Robert Price, Aug 01 2017

A228030 Primes of the form 7^n + 6.

Original entry on oeis.org

7, 13, 349, 33232930569607, 2651730845859653471779023381607
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2013

Keywords

Crossrefs

Cf. A217130 (associated n).
Cf. Primes of the form k^n + h: A092506 (k=2, h=1), A057733 (k=2, h=3), A123250 (k=2, h=5), A104066 (k=2, h=7), A104070 (k=2, h=9), A057735 (k=3, h=2), A102903 (k=3, h=4), A102870 (k=3, h=8), A102907 (k=3, h=10), A290200 (k=4, h=1), A182330 (k=5, h=2), A102910 (k=5, h=8), A182331 (k=6, h=1), A104118 (k=6, h=5), A104115 (k=6, h=7), A104065 (k=7, h=4), this sequence (k=7, h=6), A144360 (k=8, h=7), A145440 (k=8, h=9), A228034 (k=9, h=2), A159352 (k=10, h=3), A159031 (k=10, h=7).

Programs

  • Magma
    [a: n in [0..300] | IsPrime(a) where a is  7^n+6];
  • Mathematica
    Select[Table[7^n + 6, {n, 0, 300}], PrimeQ]

Extensions

Corrected cross-references - Robert Price, Aug 01 2017

A228031 Primes of the form 7^n + 10.

Original entry on oeis.org

11, 17, 59, 353, 2411, 117659, 823553, 1977326753, 9387480337647754305659, 3219905755813179726837617, 44567640326363195900190045974568017, 616873509628062366290756156815389726793178417, 30226801971775055948247051683954096612865741953
Offset: 1

Views

Author

Vincenzo Librandi, Aug 11 2013

Keywords

Crossrefs

Cf. A217132 (associated n).
Cf. Primes of the form k^n + h: A092506 (k=2, h=1), A057733 (k=2, h=3), A123250 (k=2, h=5), A104066 (k=2, h=7), A104070 (k=2, h=9), A057735 (k=3, h=2), A102903 (k=3, h=4), A102870 (k=3, h=8), A102907 (k=3, h=10), A290200 (k=4, h=1), A182330 (k=5, h=2), A102910 (k=5, h=8), A182331 (k=6, h=1), A104118 (k=6, h=5), A104115 (k=6, h=7), A104065 (k=7, h=4), this sequence (k=7, h=10), A144360 (k=8, h=7), A145440 (k=8, h=9), A228034 (k=9, h=2), A159352 (k=10, h=3), A159031 (k=10, h=7).

Programs

  • Magma
    [a: n in [0..300] | IsPrime(a) where a is  7^n+10];
  • Mathematica
    Select[Table[7^n + 10, {n, 0, 300}], PrimeQ]

Extensions

Corrected cross-references - Robert Price, Aug 01 2017
Showing 1-10 of 15 results. Next