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 1-5 of 5 results.

A352711 The left Aurifeuillian factor of p^p - 1 for primes p congruent to 1 (mod 4).

Original entry on oeis.org

11, 1803647, 2699538733, 112663560435723374699, 6243610407478181159725577611, 67643278270835231300426724641533, 253382315888712050791030544452181354268272663, 133904013361225746608283522164245432446284642589451147, 4429523820749528526448423858097183945539957285504166342434080091097
Offset: 1

Views

Author

Patrick A. Thomas, Mar 30 2022

Keywords

Comments

For prime factorizations of p^p - 1 see A125135.
Named after the French mathematician Léon-François-Antoine Aurifeuille (1822-1882). - Bernard Schott, Nov 04 2022

Examples

			112663560435723374699 is the smaller Aurifeuillian factor of 29^29-1, and 29 is the 4th term of A002144, so a(4) = 112663560435723374699.
		

Crossrefs

Formula

If R is (p^p-1)/(p-1), where p == 1 (mod 4) and p > 5, then an approximation of the left Aurifeuillian factor of R is (1/e) * sqrt(R/(1+z)), where z =
2/(3p) + 28/(45p^2) + 1706/(2835p^3) if p=1,79,109,121,151 or 169 (mod 210),
2/(3p) + 28/(45p^2) + 86/(2835p^3) if p=19,31,61,139,181 or 199 (mod 210),
2/(3p) - 8/(45p^2) + 194/(2835p^3) if p=37,43,67,127,163 or 193 (mod 210),
2/(3p) - 8/(45p^2) - 1426/(2835p^3) if p=13,73,97,103,157 or 187 (mod 210),
-2/(3p) - 8/(45p^2) + 1426/(2835p^3) if p=23,53,107,113,137 or 197 (mod 210),
-2/(3p) - 8/(45p^2) - 194/(2835p^3) if p=17,47,83,143,167 or 173 (mod 210),
-2/(3p) + 28/(45p^2) - 86/(2835p^3) if p=11,29,71,149,179 or 191 (mod 210),
-2/(3p) + 28/(45p^2) - 1706/(2835p^3) if p=41,59,89,101,131 or 209 (mod 210).

A352400 a(n) is the left Aurifeuillian factor of p^p + 1 for A002145(n), where A002145 lists the primes congruent to 3 (mod 4).

Original entry on oeis.org

1, 113, 58367, 113631466919, 348275601426959, 8403855868042458448127, 7248206084007410402911299180581471, 105318477338066161993242388018074119617, 830220061043693789623432394289631761145130727636121
Offset: 1

Views

Author

Patrick A. Thomas, Jun 08 2022

Keywords

Comments

For prime factorizations of p^p + 1 see A125136.

Examples

			105318477338066161993242388018074119617 is the smaller Aurifeuillian factor of 47^47 + 1, and 47 is the 8th term of A002145, so it is a(8).
		

Crossrefs

Formula

If R is (p^p+1)/(p+1), where p == 3 (mod 4) and p > 7, then an approximation of the left Aurifeuillian factor of R is (1/e) * sqrt(R/(1+z)), where z =
2/(3p) + 28/(45p^2) + 1706/(2835p^3) if p=1,79,109,121,151 or 169 (mod 210),
2/(3p) + 28/(45p^2) + 86/(2835p^3) if p=19,31,61,139,181 or 199 (mod 210),
2/(3p) - 8/(45p^2) + 194/(2835p^3) if p=37,43,67,127,163 or 193 (mod 210),
2/(3p) - 8/(45p^2) - 1426/(2835p^3) if p=13,73,97,103,157 or 187 (mod 210),
-2/(3p) - 8/(45p^2) + 1426/(2835p^3) if p=23,53,107,113,137 or 197 (mod 210),
-2/(3p) - 8/(45p^2) - 194/(2835p^3) if p=17,47,83,143,167 or 173 (mod 210),
-2/(3p) + 28/(45p^2) - 86/(2835p^3) if p=11,29,71,149,179 or 191 (mod 210),
-2/(3p) + 28/(45p^2) - 1706/(2835p^3) if p=41,59,89,101,131 or 209 (mod 210).

A352401 The right Aurifeuillian factor of p^p + 1 for primes p congruent to 3 (mod 4).

Original entry on oeis.org

7, 911, 407353, 870542161121, 2498077661567473, 63472256064447557254913, 54382651771205224279713471565249817, 767102704711961850109296220485687497279, 6066304600323886604542912453739225327712511596287519
Offset: 1

Views

Author

Patrick A. Thomas, Jun 08 2022

Keywords

Comments

For prime factorizations of p^p + 1 see A125136.

Examples

			870542161121 is the larger Aurifeuillian factor of 19^19 + 1, and 19 is the 4th term of A002145, so a(4) = 870542161121.
		

Crossrefs

A356518 Maximal numerators in approximations to the Aurifeuillian factors of p^p +- 1.

Original entry on oeis.org

2, 28, 1706, 25082, 816634, 157704814
Offset: 1

Views

Author

Patrick A. Thomas, Aug 10 2022

Keywords

Comments

If R=(p^p+-1)/(p+-1) then the left Aurifeuillian factor of R is (1/e)*sqrt(R/(1+z)), where z = Sum_{n>=1} r(n)/p^n and r(n) is a rational number in Q; a(n) is the numerator of r(n). r(7) appears to be about 0.572082, but there is insufficient precision to identify a(7).

Examples

			The r(n) are 2/3, 28/45, 1706/2835, 25082/42525, 816634/1403325, ...
		

Crossrefs

Cf. A356519 (denominators), A352711, A352732, A352400, A352401.

A356519 Denominators in approximations to the Aurifeuillian factors of p^p +- 1.

Original entry on oeis.org

3, 45, 2835, 42525, 1403325, 273648375
Offset: 1

Views

Author

Patrick A. Thomas, Aug 10 2022

Keywords

Comments

a(1) = 3 = 4! / 2^3
a(2) = 3^2 * 5 = 6! / 2^4
a(3) = 3^4 * 5 * 7 = 8! / 2^7 * 3^2
a(4) = 3^5 * 5^2 * 7 = 10! / 2^8 * 3
a(5) = 3^6 * 5^2 * 7 * 11 = 12! / 2^10 * 3

Crossrefs

Cf. A356518 (numerators), A352711, A352732, A352400, A352401.
Showing 1-5 of 5 results.