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.

Previous Showing 11-17 of 17 results.

A047272 Primes p such that p == 1 (mod 4) and Fibonacci((p-1)/4) is divisible by p.

Original entry on oeis.org

61, 89, 109, 149, 269, 389, 401, 421, 521, 661, 701, 761, 769, 809, 821, 829, 1009, 1049, 1069, 1181, 1249, 1289, 1301, 1361, 1381, 1409, 1429, 1601, 1721, 1901, 1949, 2081, 2089, 2141, 2221, 2269, 2309, 2341, 2381, 2441, 2549, 2729, 2741, 2749, 2789
Offset: 1

Views

Author

Keywords

Comments

There are typos in Theorems 1 and 2 of Lehmer's paper. The condition a == 1 (mod 4) should be a == 1 (mod 2). - Eric Rowland, May 20 2018

Crossrefs

For nonprimes see A091982.

Programs

  • Mathematica
    Select[Prime[Range[400]], Function[p, Mod[p, 4] == 1 && Divisible[Fibonacci[(p - 1)/4], p]]] (* Eric Rowland, May 20 2018 *)

Extensions

More terms from James Sellers, Jan 25 2000
New Name from Eric Rowland, May 20 2018

A047651 Minimal positive value of tau modulo primes in A047650.

Original entry on oeis.org

6, 10, 23, 14, 82, 144, 112, 22, 122, 100, 173, 171, 92, 339, 343, 228, 383, 458, 326, 460, 407, 485, 405, 157, 83, 125, 530, 606, 176, 136, 601, 42, 321, 236, 364, 842, 46, 914, 612, 676, 380, 535, 335, 393, 54, 123, 1209, 1298, 812, 1196, 1371, 252, 314, 851, 524, 1157
Offset: 1

Views

Author

Keywords

Comments

Since sqrt(5) mod p is determined up to a sign, there are two values that tau mod p can take.
Minimal positive solution to the equation x^2 - x - 1 = 0 modulo p for primes p in A047650.

Crossrefs

Cf. A047650.

Extensions

Edited and extended by Max Alekseyev, Feb 06 2010

A168172 Least prime p == -1 (mod n) that divides Fibonacci((p+1)/n), or 0 if no such prime exists.

Original entry on oeis.org

2, 13, 47, 0, 0, 113, 307, 0, 233, 0, 967, 0, 2417, 797, 0, 0, 1087, 233, 5737, 0, 5417, 5653, 1103, 0, 0, 2417, 4373, 0, 6263, 0, 25357, 0, 3167, 42533, 0, 0, 4513, 5737, 2417, 0, 61417, 5417, 32507, 0, 0, 36017, 1597, 0, 97607, 0, 27947, 0, 42293, 4373, 0, 0
Offset: 1

Views

Author

M. F. Hasler, Nov 28 2009

Keywords

Comments

Max Alekseyev has proved (cf. link) that a(n)=0 if n is a multiple of 4 or 5; for all other n, a prime a(n) with the required property seems to exist.

Crossrefs

Cf. A168171 (least p | F[(p-1)/n]), A122487 (p | F[(p+1)/2]), A047652 (p | F[(p-1)/3]), A001583 (Artiads: p | F[(p-1)/5]), A125252 (p | F[(p+1)/7]), A125253 (p | F[(p-1)/7]).

Programs

  • PARI
    A168172(n) = n%4 && n%5 && forstep(p=n-1,1e9,n, isprime(p) || next; fibonacci((p+1)/n)%p || return(p))

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())

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.

A271171 Erroneous version of A270798.

Original entry on oeis.org

5081, 5591, 6211, 6271, 8581, 8861, 9011, 9661
Offset: 1

Views

Author

Keywords

Comments

The correct first term is 5281, not 5081 as given in [Lehmer].
Previous Showing 11-17 of 17 results.