The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A285721 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A285721

Square array read by antidiagonals: A(n,k) = number of steps in simple Euclidean algorithm for gcd(n,k) to reach the termination test n=k, read by antidiagonals as A(1,1), A(1,2), A(2,1), A(1,3), A(2,2), A(3,1), etc.
(history; published version)

#25 by N. J. A. Sloane at Sun Mar 28 19:34:46 EDT 2021

STATUS

proposed

approved

#24 by F. Chapoton at Sun Mar 28 15:34:56 EDT 2021

STATUS

editing

proposed

#23 by F. Chapoton at Sun Mar 28 15:34:46 EDT 2021

PROG

for n in range(1, 21): print ([A(n - k + 1, k) for k in range(1, n + 1)] ) # Indranil Ghosh, May 03 2017

STATUS

approved

editing

Discussion

Sun Mar 28

15:34

F. Chapoton: adapt py code to py3

#22 by N. J. A. Sloane at Sat Dec 07 12:18:29 EST 2019

PROG

for n in xrangerange(1, 21): print [A(n - k + 1, k) for k in xrangerange(1, n + 1)] # Indranil Ghosh, May 03 2017

Discussion

Sat Dec 07

12:18

OEIS Server: https://oeis.org/edit/global/2837

#21 by Jon E. Schoenfield at Sat Jul 07 16:22:20 EDT 2018

STATUS

editing

approved

#20 by Jon E. Schoenfield at Sat Jul 07 16:22:17 EDT 2018

EXAMPLE

The top left 18x18 18 X 18 corner of the array:

STATUS

approved

editing

#19 by Bruno Berselli at Wed May 03 11:37:23 EDT 2017

STATUS

reviewed

approved

#18 by Joerg Arndt at Wed May 03 11:35:00 EDT 2017

STATUS

proposed

reviewed

#17 by Indranil Ghosh at Wed May 03 09:26:40 EDT 2017

STATUS

editing

proposed

#16 by Indranil Ghosh at Wed May 03 09:26:13 EDT 2017

PROG

(Python)

def A(n, k): return 0 if n==k else 1 + A(abs(n - k), min(n, k))

for n in xrange(1, 21): print [A(n - k + 1, k) for k in xrange(1, n + 1)] # Indranil Ghosh, May 03 2017

STATUS

approved

editing