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 1-4 of 4 results.

A039705 a(n) = n-th prime modulo 7.

Original entry on oeis.org

2, 3, 5, 0, 4, 6, 3, 5, 2, 1, 3, 2, 6, 1, 5, 4, 3, 5, 4, 1, 3, 2, 6, 5, 6, 3, 5, 2, 4, 1, 1, 5, 4, 6, 2, 4, 3, 2, 6, 5, 4, 6, 2, 4, 1, 3, 1, 6, 3, 5, 2, 1, 3, 6, 5, 4, 3, 5, 4, 1, 3, 6, 6, 3, 5, 2, 2, 1, 4, 6, 3, 2, 3, 2, 1, 5, 4, 5, 2, 3, 6, 1, 4, 6, 5, 2, 1, 2, 6, 1, 5, 3, 4, 1, 2, 6, 5, 3, 5, 2, 1, 4, 3, 2, 4
Offset: 1

Views

Author

Keywords

Comments

a(A049084(A045370(n-1))) is even; a(A049084(A045415(n-1))) is odd. - Reinhard Zumkeller, Feb 25 2008

Crossrefs

Programs

Formula

Sum_k={1..n} a(k) ~ (7/2)*n. - Amiram Eldar, Dec 11 2024

A045429 Primes congruent to {1, 3} mod 5.

Original entry on oeis.org

3, 11, 13, 23, 31, 41, 43, 53, 61, 71, 73, 83, 101, 103, 113, 131, 151, 163, 173, 181, 191, 193, 211, 223, 233, 241, 251, 263, 271, 281, 283, 293, 311, 313, 331, 353, 373, 383, 401, 421, 431, 433, 443, 461, 463, 491, 503, 521, 523, 541, 563, 571, 593, 601, 613, 631, 641
Offset: 1

Views

Author

Keywords

Comments

A039703(A049084(a(n))) = odd; complement of A045356. - Reinhard Zumkeller, Feb 25 2008

Crossrefs

Programs

  • Magma
    [ p: p in PrimesUpTo(600) | p mod 5 in {1,3} ]; // Vincenzo Librandi, Aug 13 2012
  • Mathematica
    Select[Prime[Range[200]], MemberQ[{1, 3}, Mod[#, 5]] &] (* Vincenzo Librandi, Aug 13 2012 *)
    Select[Prime[Range[200]], OddQ[Mod[#, 5]] &] (* Zak Seidov, Aug 31 2012 *)

A045370 Primes congruent to {0, 2, 4, 6} mod 7.

Original entry on oeis.org

2, 7, 11, 13, 23, 37, 41, 53, 67, 79, 83, 97, 107, 109, 137, 139, 149, 151, 163, 167, 179, 181, 191, 193, 223, 233, 251, 263, 277, 293, 307, 317, 331, 347, 349, 359, 373, 389, 401, 419, 431, 433, 443, 457, 461
Offset: 1

Views

Author

Keywords

Comments

A039705(A049084(a(n))) = even; complement of A045415. - Reinhard Zumkeller, Feb 25 2008

Crossrefs

Programs

  • Magma
    [ p: p in PrimesUpTo(600) | p mod 7 in {0..6 by 2} ]; // Vincenzo Librandi, Aug 10 2012
  • Mathematica
    Select[Prime[Range[300]],MemberQ[{0,2,4,6},Mod[#,7]]&] (* Vincenzo Librandi, Aug 10 2012 *)
    Select[Prime[Range[110]], EvenQ[Mod[#, 7]] & ] (* Bruno Berselli, Aug 31 2012 *)

A137978 Primes congruent to {1, 3, 5, 7, 9} modulo 11.

Original entry on oeis.org

3, 5, 7, 23, 29, 31, 47, 53, 67, 71, 73, 89, 97, 113, 137, 139, 157, 163, 179, 181, 199, 223, 227, 229, 251, 269, 271, 293, 311, 313, 317, 331, 337, 353, 359, 379, 383, 397, 401, 419, 421, 443, 449, 463, 467, 487, 491, 509, 557, 577, 599, 601, 617, 619, 641
Offset: 1

Views

Author

Reinhard Zumkeller, Feb 25 2008

Keywords

Comments

A039709(A049084(a(n))) = odd; complement of A137977.

Crossrefs

Programs

  • Magma
    [ p: p in PrimesUpTo(740) | p mod 11 in {1, 3, 5, 7, 9} ] // Vincenzo Librandi, Jan 25 2011
  • Mathematica
    Select[Flatten[# + {1, 3, 5, 7, 9}&/@(11Range[0, 80])], PrimeQ] (* Harvey P. Dale, Jan 15 2011 *)
Showing 1-4 of 4 results.