The On-Line Encyclopedia of Integer Sequences (OEIS)

Revisions by Giorgos Kalogeropoulos (See also Giorgos Kalogeropoulos's wiki page)

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A374388

a(n) is the maximal absolute value of the determinant of an n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the first n-1 primes off-diagonal.
(history; published version)

#7 by Giorgos Kalogeropoulos at Fri Jul 12 11:54:24 EDT 2024

STATUS

editing

proposed

#6 by Giorgos Kalogeropoulos at Fri Jul 12 11:54:02 EDT 2024

DATA

1, 0, 4, 36, 324, 15164, 2287607, 162104000, 37905894000, 4059346088384, 718058901423168, 221630954408019520

EXTENSIONS

a(11) from Giorgos Kalogeropoulos, Jul 12 2024

STATUS

approved

editing

A374387

a(n) is the maximal determinant of an n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the first n-1 primes off-diagonal.
(history; published version)

#7 by Giorgos Kalogeropoulos at Wed Jul 10 12:44:38 EDT 2024

STATUS

editing

proposed

#6 by Giorgos Kalogeropoulos at Wed Jul 10 12:44:25 EDT 2024

DATA

1, 0, -4, 36, 129, 3340, 2287607, 162104000, 16943055268, 4059346088384, 474967482901952, 221630954408019520

EXTENSIONS

a(11) from Giorgos Kalogeropoulos, Jul 10 2024

STATUS

approved

editing

A374386

a(n) is the minimal determinant of an n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the first n-1 primes off-diagonal.
(history; published version)

#9 by Giorgos Kalogeropoulos at Wed Jul 10 12:34:10 EDT 2024

STATUS

editing

proposed

#8 by Giorgos Kalogeropoulos at Wed Jul 10 12:33:50 EDT 2024

DATA

1, 0, -4, 24, -324, -15164, -1453072, -161765904, -37905894000, -1376219654680, -718058901423168, -163742479201610036

EXTENSIONS

a(11) from Giorgos Kalogeropoulos, Jul 10 2024

STATUS

approved

editing

A373576

Sums of maximal antiruns of prime-powers.
(history; published version)

#7 by Giorgos Kalogeropoulos at Tue Jun 18 18:01:21 EDT 2024

STATUS

editing

proposed

#6 by Giorgos Kalogeropoulos at Tue Jun 18 18:00:59 EDT 2024

DATA

2, 3, 4, 12, 8, 49, 171, 2032, 5157, 3997521, 199713082, 561678378, 10122001905, 109934112352390774

EXTENSIONS

a(14) from Giorgos Kalogeropoulos, Jun 18 2024

STATUS

approved

editing

A373453

Iterate the function x <- phi(sigma(x)). The sequence has the smallest member of cycles of length 3.
(history; published version)

#26 by Giorgos Kalogeropoulos at Tue Jun 18 04:24:53 EDT 2024

STATUS

editing

proposed

#25 by Giorgos Kalogeropoulos at Tue Jun 18 04:23:59 EDT 2024

DATA

16, 1200, 15552, 67392, 272160, 69672960000

COMMENTS

a(7) <= 2704853606400. The numbers 242595672883200000, 66217181184000000000 and 185577469193591193600 are also terms. - Giorgos Kalogeropoulos, Jun 18 2024

EXTENSIONS

a(6) from Giorgos Kalogeropoulos, Jun 18 2024

STATUS

approved

editing