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.

A091968 Primes congruent to 3 (mod 16).

Original entry on oeis.org

3, 19, 67, 83, 131, 163, 179, 211, 227, 307, 419, 467, 499, 547, 563, 643, 659, 691, 739, 787, 883, 947, 1091, 1123, 1171, 1187, 1283, 1427, 1459, 1523, 1571, 1619, 1667, 1699, 1747, 1811, 1907, 1987, 2003, 2083, 2099, 2131, 2179, 2243, 2339, 2371, 2467
Offset: 1

Views

Author

Giovanni Teofilatto, Mar 14 2004

Keywords

Comments

For any n, the equations x^4 - y^4 = a(n)*z^2 and x^4 - a(n)^2*y^4 = z^2 are not solvable in natural numbers. - Arkadiusz Wesolowski, Aug 15 2013

References

  • L. J. Mordell, Diophantine Equations, Ac. Press, p. 23.
  • Trygve Nagell, Introduction to Number Theory, Chelsea Publishing Company, NY, 1964, p. 230.

Crossrefs

Programs

Extensions

More terms from Ray Chandler, Mar 15 2004

A092022 Numbers k such that 16k + 3 is prime.

Original entry on oeis.org

0, 1, 4, 5, 8, 10, 11, 13, 14, 19, 26, 29, 31, 34, 35, 40, 41, 43, 46, 49, 55, 59, 68, 70, 73, 74, 80, 89, 91, 95, 98, 101, 104, 106, 109, 113, 119, 124, 125, 130, 131, 133, 136, 140, 146, 148, 154, 158, 161, 166, 169, 175, 176, 178, 185, 188, 199, 200, 203, 206, 208
Offset: 1

Views

Author

Ray Chandler, Mar 15 2004

Keywords

Crossrefs

Programs

Formula

a(n) = (A091968(n)-3)/16. - Zak Seidov, Mar 28 2015

A163595 Numbers k such that prime(k) == 5 (mod 9).

Original entry on oeis.org

3, 9, 13, 17, 30, 32, 35, 39, 52, 55, 62, 64, 69, 76, 79, 81, 94, 97, 103, 109, 113, 119, 132, 135, 139, 154, 160, 165, 170, 173, 176, 185, 196, 201, 208, 212, 215, 220, 223, 225, 234, 239, 245, 248, 253, 265, 270, 277
Offset: 1

Views

Author

Juri-Stepan Gerasimov, Aug 01 2009

Keywords

Comments

The asymptotic density of this sequence is 1/6 (by Dirichlet's theorem). - Amiram Eldar, Mar 02 2021

Crossrefs

Programs

  • Maple
    for n from 1 to 300 do p := ithprime(n) ; if (p mod 9 ) = 5 then printf("%d,",n) ; fi; od: # R. J. Mathar, Aug 01 2009
    A163595 := proc(n) option remember ; local a; if n = 1 then 3 ; else for a from procname(n-1)+1 do if ithprime(a) mod 9 = 5 then return(a) ; fi; end do: end if; end proc: seq(A163595(n),n=1..100) ; # R. J. Mathar, Oct 10 2009
  • Mathematica
    Select[Range[300],Mod[Prime[#],9]==5&]  (* Harvey P. Dale, Apr 25 2011 *)

Formula

A000040(a(n)) = A061240(n).
a(n) = A000720(A061240(n)).
Showing 1-3 of 3 results.