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 1-9 of 9 results.

A039706 a(n) = n-th prime modulo 8.

Original entry on oeis.org

2, 3, 5, 7, 3, 5, 1, 3, 7, 5, 7, 5, 1, 3, 7, 5, 3, 5, 3, 7, 1, 7, 3, 1, 1, 5, 7, 3, 5, 1, 7, 3, 1, 3, 5, 7, 5, 3, 7, 5, 3, 5, 7, 1, 5, 7, 3, 7, 3, 5, 1, 7, 1, 3, 1, 7, 5, 7, 5, 1, 3, 5, 3, 7, 1, 5, 3, 1, 3, 5, 1, 7, 7, 5, 3, 7, 5, 5, 1, 1, 3, 5, 7, 1, 7, 3, 1, 1, 5, 7, 3, 7, 7, 3, 3, 7, 5, 1, 3, 5, 3, 5, 3, 1, 3
Offset: 1

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Formula

Sum_k={1..n} a(k) ~ 4*n. - Amiram Eldar, Dec 11 2024

A039709 a(n) = n-th prime modulo 11.

Original entry on oeis.org

2, 3, 5, 7, 0, 2, 6, 8, 1, 7, 9, 4, 8, 10, 3, 9, 4, 6, 1, 5, 7, 2, 6, 1, 9, 2, 4, 8, 10, 3, 6, 10, 5, 7, 6, 8, 3, 9, 2, 8, 3, 5, 4, 6, 10, 1, 2, 3, 7, 9, 2, 8, 10, 9, 4, 10, 5, 7, 2, 6, 8, 7, 10, 3, 5, 9, 1, 7, 6, 8, 1, 7, 4, 10, 5, 9, 4, 1, 5, 2, 1, 3, 2, 4, 10, 3
Offset: 1

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Author

Clark Kimberling, Dec 11 1999

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Formula

a(A049084(A137977(n-1))) = even; a(A049084(A137978(n-1))) = odd. - Reinhard Zumkeller, Feb 25 2008
Sum_k={1..n} a(k) ~ (11/2)*n. - Amiram Eldar, Dec 11 2024

A242119 Primes modulo 18.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 1, 5, 11, 13, 1, 5, 7, 11, 17, 5, 7, 13, 17, 1, 7, 11, 17, 7, 11, 13, 17, 1, 5, 1, 5, 11, 13, 5, 7, 13, 1, 5, 11, 17, 1, 11, 13, 17, 1, 13, 7, 11, 13, 17, 5, 7, 17, 5, 11, 17, 1, 7, 11, 13, 5, 1, 5, 7, 11, 7, 13, 5, 7, 11, 17, 7, 13, 1, 5
Offset: 1

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Author

Vincenzo Librandi, May 05 2014

Keywords

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Cf. sequences of the type Primes mod k: A039701 (k=3), A039702 (k=4), A039703 (k=5), A039704 (k=6), A039705 (k=7), A039706 (k=8), A038194 (k=9), A007652 (k=10), A039709 (k=11), A039710 (k=12), A039711 (k=13), A039712 (k=14), A039713 (k=15), A039714 (k=16), A039715 (k=17), this sequence (k=18), A033633 (k=19), A242120(k=20), A242121 (k=21), A242122 (k=22), A229786 (k=23), A229787 (k=24), A242123 (k=25), A242124 (k=26), A242125 (k=27), A242126 (k=28), A242127 (k=29), A095959 (k=30), A110923 (k=100).

Programs

  • Magma
    [p mod(18): p in PrimesUpTo(500)];
    
  • Mathematica
    Mod[Prime[Range[100]], 18]
  • Sage
    [mod(p, 18) for p in primes(500)] # Bruno Berselli, May 05 2014

Formula

Sum_{i=1..n} a(i) ~ 9n. The derivation is the same as in the formula in A039715. - Jerzy R Borysowicz, Apr 27 2022

A039704 a(n) = n-th prime modulo 6.

Original entry on oeis.org

2, 3, 5, 1, 5, 1, 5, 1, 5, 5, 1, 1, 5, 1, 5, 5, 5, 1, 1, 5, 1, 1, 5, 5, 1, 5, 1, 5, 1, 5, 1, 5, 5, 1, 5, 1, 1, 1, 5, 5, 5, 1, 5, 1, 5, 1, 1, 1, 5, 1, 5, 5, 1, 5, 5, 5, 5, 1, 1, 5, 1, 5, 1, 5, 1, 5, 1, 1, 5, 1, 5, 5, 1, 1, 1, 5, 5, 1, 5, 1, 5, 1, 5, 1, 1, 5, 5, 1, 5, 1, 5, 5, 1, 5, 1, 5, 5, 5, 1, 1, 1, 5, 5, 5, 1
Offset: 1

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Formula

Sum_k={1..n} a(k) ~ 3*n. - Amiram Eldar, Dec 11 2024

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

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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 *)

A045415 Primes congruent to {1, 3, 5} mod 7.

Original entry on oeis.org

3, 5, 17, 19, 29, 31, 43, 47, 59, 61, 71, 73, 89, 101, 103, 113, 127, 131, 157, 173, 197, 199, 211, 227, 229, 239, 241, 257, 269, 271, 281, 283, 311, 313, 337, 353, 367, 379, 383, 397, 409, 421, 439, 449, 463, 467
Offset: 1

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Author

Keywords

Comments

A039705(A049084(a(n))) = odd; complement of A045370. - Reinhard Zumkeller, Feb 25 2008

Crossrefs

Programs

  • Magma
    [ p: p in PrimesUpTo(600) | p mod 7 in {1,3,5} ]; // Vincenzo Librandi, Aug 12 2012
  • Mathematica
    Select[Prime[Range[100]],MemberQ[{1,3,5},Mod[#,7]]&] (* Harvey P. Dale, May 15 2011 *)

A103568 Sum of the (primes > 5 modulo 7).

Original entry on oeis.org

0, 4, 10, 13, 18, 20, 21, 24, 26, 32, 33, 38, 42, 45, 50, 54, 55, 58, 60, 66, 71, 77, 80, 85, 87, 91, 92, 93, 98, 102, 108, 110, 114, 117, 119, 125, 130, 134, 140, 142, 146, 147, 150, 151, 157, 160, 165, 167, 168, 171, 177, 182, 186, 189, 194, 198, 199, 202, 208, 214
Offset: 1

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Author

Roger L. Bagula, Mar 23 2005

Keywords

Crossrefs

Programs

  • Mathematica
    a = Table[Sum[Mod[Prime[i + 3], 7], {i, 1, n}], {n, 1, 200}]

Formula

a(n+1)-a(n) = A039705(n+4).

A122601 a(n)=(n-th prime +1) modulo 7.

Original entry on oeis.org

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

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Author

Zak Seidov, Sep 24 2006

Keywords

Comments

a(n)=1 only for n=4; frequences f(m) of other values are almost equal, e.g., for n=1..1000, f(m=0..6): 166,1,165,166,168,164,170.

Crossrefs

Cf. A039705.

Programs

  • Mathematica
    Table[Mod[(Prime[n]+1),7],{n,1000}]

Formula

a(n)= (A039705(n)+1) mod 7

A252728 Numbers k such that exactly 5 consecutive primes starting with prime(k) are congruent to the same value modulo 7.

Original entry on oeis.org

70872, 191056, 204048, 215955, 216351, 251872, 266249, 346159, 431099, 433456, 443366, 461372, 517528, 654361, 664677, 793519, 841521, 865347, 904987, 918479, 1056902, 1060733, 1063487, 1134245, 1140824, 1158526
Offset: 1

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Author

Zak Seidov, Feb 16 2015

Keywords

Comments

Or, numbers k such A039705(k) = ... = A039705(k+4), but not A039705(k+5).

Examples

			k=70872, {A000040(k), ..., A000040(k+4)} = {894287, 894301, 894329, 894343, 894371} == 2 (mod 7).
		

Crossrefs

Showing 1-9 of 9 results.