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 1-6 of 6 results.

A270801 Septic hyperartiads: septic artiads (A270800) for which 7 is a 7th power residue.

Original entry on oeis.org

665897, 741413, 794207, 859601, 876611, 892627, 980911, 1102249, 1116977, 1123879, 1129213, 1163653, 1228543, 1237139, 1393771, 1434553, 1453019, 1471079, 1513163, 1570577, 1588133, 1608769, 1638211, 1638743, 1645253, 1670887, 1702933, 1704137, 1785337
Offset: 1

Views

Author

N. J. A. Sloane, Apr 01 2016, typo corrected Apr 02 2016

Keywords

Crossrefs

Programs

  • Sage
    def is_septic_hyperartiad(n) :
        if not (n % 14 == 1 and is_prime(n)) : return false
        R. = PolynomialRing(GF(n))
        return 7.powermod((n-1)//7, n) == 1 and all(r[0]^((n-1)//7) == 1 for r in (t^3 + t^2 - 2*t - 1).roots())
    # Eric M. Schmidt, Apr 02 2016

Extensions

Definition corrected by and more terms from Eric M. Schmidt, Apr 02 2016

A271263 Septic artiads (A270800) congruent to 1 mod 98 and for which 2 is a 7th power residue.

Original entry on oeis.org

874651, 941879, 1074277, 1080451, 1396697, 2024387, 2546237, 2807603, 3267419, 3324847, 3436273, 3465673, 3851009, 4150301, 4219979, 4367567, 4651963, 4762507, 5173813, 5308759, 5398919, 5474477, 5552191, 5710363, 6248579, 6391267, 6575507, 6627251, 6791107
Offset: 1

Views

Author

Eric M. Schmidt, Apr 03 2016

Keywords

Crossrefs

Programs

  • Sage
    def isa(n) :
        if not (n % 98 == 1 and is_prime(n)) : return False
        R. = PolynomialRing(GF(n))
        return 2.powermod((n-1)//7, n) == 1 and all(r[0]^((n-1)//7) == 1 for r in (t^3 + t^2 - 2*t - 1).roots())

A271264 Septic artiads (A270800) congruent to 1 mod 98 and for which 7 is a 7th power residue.

Original entry on oeis.org

876611, 1163653, 1471079, 1608769, 2367289, 2368759, 2538103, 2564857, 2621501, 2693629, 2774381, 3120713, 3495269, 3498797, 3636781, 3974881, 4240853, 4376681, 4571309, 4654217, 4702433, 4867171, 5047883, 5066993, 5629121, 5644213, 5760343, 5779649, 6262397
Offset: 1

Views

Author

Eric M. Schmidt, Apr 03 2016

Keywords

Comments

Septic hyperartiads (A270801) congruent to 1 mod 98.

Crossrefs

Programs

  • Sage
    def isa(n) :
        if not (n % 98 == 1 and is_prime(n)) : return False
        R. = PolynomialRing(GF(n))
        return 7.powermod((n-1)//7, n) == 1 and all(r[0]^((n-1)//7) == 1 for r in (t^3 + t^2 - 2*t - 1).roots())

A271247 Erroneous version of A270800.

Original entry on oeis.org

14197, 21617, 25801, 24977, 25999
Offset: 1

Views

Author

Keywords

Comments

The correct third term is 23801, not 25801 as given in [Lehmer].

A001583 Artiads: the primes p == 1 (mod 5) for which Fibonacci((p-1)/5) is divisible by p.

Original entry on oeis.org

211, 281, 421, 461, 521, 691, 881, 991, 1031, 1151, 1511, 1601, 1871, 1951, 2221, 2591, 3001, 3251, 3571, 3851, 4021, 4391, 4441, 4481, 4621, 4651, 4691, 4751, 4871, 5081, 5281, 5381, 5531, 5591, 5641, 5801, 5881, 6011, 6101, 6211, 6271, 6491, 6841
Offset: 1

Views

Author

Keywords

Comments

From A.H.M. Smeets, Nov 15 2023: (Start)
Mean gap size between two consecutive terms at p: ~ 20*log(p) (see E. Lehmer).
In E. Lehmer, Artiads characterized, she counted in the table on p. 122 the primes p for which p == 1 (mod 5) instead of all primes. As a result, in the corollary on p. 121, the 20% becomes 5% (or 1/20 instead of 1/5). (End)

References

  • N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
  • N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

Crossrefs

Cf. A047650, A000045, A024894, subsequence of A030430.
See also A270798 (a subsequence), A270800.

Programs

  • Haskell
    a001583 n = a001583_list !! (n-1)
    a001583_list = filter
       (\p -> mod (a000045 $ div (p - 1) 5) p == 0) a030430_list
    -- Reinhard Zumkeller, Aug 15 2013
    
  • Mathematica
    Select[ Prime[ Range[1000]], Mod[#, 5] == 1 && Divisible[ Fibonacci[(# - 1)/5], #] &] (* Jean-François Alcover, Jun 22 2012 *)
  • PARI
    fibmod(n, m)=((Mod([1, 1; 1, 0], m))^n)[1, 2]
    list(lim)=my(v=List()); forprime(p=11,lim, if(p%5==1 && fibmod(p\5,p)==0, listput(v,p))); Vec(v) \\ Charles R Greathouse IV, Feb 06 2017

Formula

From A.H.M. Smeets, Nov 15 2023: (Start)
Equals {prime(m): A296240(m) == 0 (mod 5)}.
a(n) ~ prime(20*n). (End)

Extensions

More terms from James Sellers, Jan 25 2000
Edited by N. J. A. Sloane, Apr 01 2016

A271265 Primes congruent to 1 mod 14 represented by x^2 + 343y^2.

Original entry on oeis.org

379, 743, 827, 1373, 1499, 1597, 2213, 2647, 2843, 3221, 3571, 4243, 4397, 4621, 5657, 6133, 6217, 6329, 6427, 8443, 8513, 8597, 8737, 8807, 8863, 9059, 9871, 10529, 10781, 11159, 11173, 11551, 11579, 12377, 12517, 12671, 12713, 13693, 13903, 14029, 14197
Offset: 1

Views

Author

Eric M. Schmidt, Apr 03 2016

Keywords

Comments

Includes the septic artiads (A270800).

Crossrefs

Cf. A270800.
Showing 1-6 of 6 results.