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.

A243449 Primes of the form n^2 + 14.

Original entry on oeis.org

23, 239, 743, 1103, 2039, 5639, 7583, 8663, 27239, 33503, 38039, 42863, 59063, 81239, 88223, 91823, 119039, 131783, 140639, 164039, 189239, 205223, 245039, 263183, 288383, 328343, 342239, 378239, 393143, 400703, 431663, 439583, 514103, 660983, 710663, 950639
Offset: 1

Views

Author

Vincenzo Librandi, Jun 05 2014

Keywords

Crossrefs

Cf. A121250 (associated n).
Cf. primes of the form n^2+k: A144255 (k=1), A056899 (k=2), A049423 (k=3), A005473 (k=4), A056905 (k=5), A056909 (k=6), A079138 (k=7), A138338 (k=8), A138353 (k=9), A138355 (k=10), A138362 (k=11), A138368 (k=12), A138375 (k=13), this sequence (k=14), A243450 (k=15), A243451 (k=16), A228244 (k=17), A174812 (k=42).

Programs

  • Magma
    [a: n in [0..1000] | IsPrime(a) where a is n^2+14];
  • Mathematica
    Select[Table[n^2 + 14, {n, 0, 2000}], PrimeQ]
    Select[Range[1,1001,2]^2+14,PrimeQ] (* Harvey P. Dale, May 30 2023 *)

A264790 Numbers k such that k^2 + 17 is prime.

Original entry on oeis.org

0, 6, 24, 60, 66, 78, 90, 108, 144, 162, 174, 186, 234, 252, 294, 300, 318, 330, 336, 342, 372, 396, 420, 438, 456, 462, 468, 498, 528, 594, 636, 648, 654, 672, 720, 750, 798, 804, 834, 858, 888, 924, 930, 966, 984, 990, 1014, 1026, 1032, 1086, 1158, 1194, 1200
Offset: 1

Views

Author

Ilya Gutkovskiy, Nov 25 2015

Keywords

Comments

Primes of the form k^2 + 17 have a representation as a sum of 2 squares because they belong to A002144.
All terms are multiple of 6.

Examples

			a(3) = 24 because 24^2 + 17 = 593, which is prime.
		

Crossrefs

Cf. A228244 (associated primes).
Other sequences of the type "Numbers n such that n^2 + k is prime": A005574 (k=1), A067201 (k=2), A049422 (k=3), A007591 (k=4), A078402 (k=5), A114269 (k=6), A114270 (k=7), A114271 (k=8), A114272 (k=9), A114273 (k=10), A114274 (k=11), A114275 (k=12), A113536 (k=13), A121250 (k=14), A121982 (k=15), A122062 (k=16).

Programs

  • Magma
    [n: n in [0..1200 ] | IsPrime(n^2+17)]; // Vincenzo Librandi, Nov 25 2015
  • Mathematica
    Select[Range[0, 1200], PrimeQ[#^2 + 17] &] (* Michael De Vlieger, Nov 25 2015 *)
  • PARI
    for(n=0, 1e3, if(isprime(n^2+17), print1(n, ", "))) \\ Altug Alkan, Nov 25 2015
    

Formula

A000005(A241847(a(n))) = 2.
A241847(a(n)) = A228244(n).

Extensions

Edited by Bruno Berselli, Nov 26 2015

A178050 n=x^2+17, n and n+2 are prime.

Original entry on oeis.org

17, 26261, 90017, 138401, 176417, 562517, 788561, 2022101, 2683061, 4743701, 5336117, 9622421, 11614481, 13927841, 21344417, 21734261, 22184117, 38192417, 59629301, 64448801, 68558417, 79923617, 82301201, 89302517, 90098081, 91814741, 95648417
Offset: 1

Views

Author

John L. Drost, Dec 16 2010

Keywords

Examples

			17=0^2+17, and 19 are prime.
26261=162^2+17 and 26263 are prime.
		

Crossrefs

Subsequence of A228244.

Programs

  • PARI
    isok(n) = isprime(n) && isprime(n+2) && issquare(n-17); \\ Michel Marcus, Aug 18 2013

Extensions

a(26)-a(27) from Michel Marcus, Aug 18 2013
Showing 1-3 of 3 results.