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 1-3 of 3 results.

A094479 Primes of the form p^4 + 16 where p is also a prime.

Original entry on oeis.org

97, 641, 2417, 14657, 83537, 130337, 279857, 1874177, 2825777, 12117377, 13845857, 25411697, 38950097, 88529297, 294499937, 373301057, 1026625697, 2472973457, 2655237857, 2750058497, 3373402577, 6414247937, 9597924977
Offset: 1

Views

Author

Labos Elemer, Jun 01 2004

Keywords

Comments

p is in A158361. - Zak Seidov, Jul 08 2020

Crossrefs

Cf. A158361.

Programs

  • Magma
    [a: p in PrimesUpTo(400) | IsPrime(a) where a is p^4+16]; // Vincenzo Librandi, Jun 18 2014
  • Mathematica
    Select[Table[p^4+16,{p,Prime[Range[80]]}],PrimeQ] (* Harvey P. Dale, Jun 17 2014 *)

A132260 Array T(k,n) = n-th prime p such that 2^2^k + p^2^k is prime, k>2, read by antidiagonals.

Original entry on oeis.org

13, 89, 137, 29, 107, 223, 37, 59, 127, 331, 113, 53, 101, 139, 389, 113, 223, 181, 103, 173, 491, 13, 1223, 5279, 491, 109, 179, 563, 1151, 181, 1277, 7517, 547, 181, 229, 647, 43, 2153, 761, 1993, 8039, 619, 199, 233, 701, 53, 271, 3559, 4133, 2399, 9833, 661, 379, 349, 773
Offset: 3

Views

Author

Jonathan Vos Post, Aug 15 2007

Keywords

Comments

These were computed by Ignacio Larrosa CaƱestro, who cautions that some are only probable primes. The k=3 row is A157950. The main diagonal is A132261.

Examples

			The array begins:
   n  |   1    2    3    4    5    6     7     8     9    10
  ----+--------------------------------------------------------
  k=3 |  13  137  223  331  389  491   563   647   701   773
  k=4 |  89  107  127  139  173  179   229   233   349   421
  k=5 |  29   59  101  103  109  181   199   379   769   881
  k=6 |  37   53  181  491  547  619   661   677   911   941
  k=7 | 113  223 5279 7517 8039 9833 12197 13757 21467 23447
  k=8 | 113 1223 1277 1993 2399 9349  9739 10211 10973 11059
		

Crossrefs

Extensions

More terms from Jinyuan Wang, Feb 01 2022

A158477 Primes p with property that Q(p) = p^32+2^32 is prime.

Original entry on oeis.org

29, 59, 101, 103, 109, 181, 199, 379, 769, 881, 919, 977, 1097, 1213, 1303, 1583, 2099, 2113, 2441, 2521, 2617, 2777, 3067, 3739, 4133, 4289, 4519, 4931, 5039, 5113, 5227, 5417, 5743, 5783, 6143, 6373, 6691, 8053, 8209, 8287, 8513, 9109, 9203, 9689, 9787, 9923, 9941
Offset: 1

Views

Author

Ulrich Krug (leuchtfeuer37(AT)gmx.de), Mar 20 2009

Keywords

Comments

1) Q=(p^16)^2+(2^16)^2 only for Q=4k+1 because of Fermat/Euler/Lagrange theorem concerning prime as sum of two squares.
2) It is conjectured that sequence a(n) is infinite.
3) Note the twin prime: a(3)=101, a(4)=103.
The next set of twins is a(101)=30557, a(102)=30559. - Robert Israel, Apr 05 2016

Examples

			p=3: 3^32+2^32=1853024483819137 = 1153 x 1607133116929 no prime;
also for following primes p=5, 7, 11, 13, 17, 19, 23: Q(p) no prime;
p=29: 29^32+2^32=62623297589448778360828428329074752313100292737 is prime => a(1)=29.
		

References

  • Richard E. Crandall, Carl Pomerance, Prime Numbers: A Computational Perspective, Springer 2001.
  • Leonard E. Dickson, History of the Theory of Numbers, Dover Pub. Inc., 2005.

Crossrefs

Programs

  • Maple
    select(t -> isprime(t) and isprime(t^32 + 2^32), [seq(i,i=3..10000,2)]); # Robert Israel, Apr 05 2016
  • Mathematica
    With[{c=2^32},Select[Prime[Range[1300]],PrimeQ[#^32+c]&]] (* Harvey P. Dale, May 04 2018 *)
  • PARI
    isA158477(n) = isprime(n) && isprime(n^32+4294967296) \\ Michael B. Porter, Dec 17 2009
    
  • PARI
    lista(nn) = forprime(p=3, nn, if(ispseudoprime(p^32+2^32), print1(p, ", "))); \\ Altug Alkan, Apr 05 2016

Formula

n^32+2^32 and n to be prime.
Showing 1-3 of 3 results.