The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A282389 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing entries 1-10 | older changes

A282389

Number of squares in triangle-shaped polyominoes obtained by adding three identical polyominoes to the previous one, starting with one L-tetromino.
(history; published version)

#16 by Joerg Arndt at Wed Apr 25 11:49:56 EDT 2018

STATUS

reviewed

approved

#15 by Michel Marcus at Wed Apr 25 09:22:29 EDT 2018

STATUS

proposed

reviewed

#14 by Jon E. Schoenfield at Wed Apr 25 01:30:38 EDT 2018

STATUS

editing

proposed

#13 by Jon E. Schoenfield at Wed Apr 25 01:30:35 EDT 2018

PROG

print(sum(m)) # print(w) for widths of the polyminoespolyominoes

STATUS

approved

editing

#12 by Charles R Greathouse IV at Tue Feb 14 22:35:19 EST 2017

STATUS

proposed

approved

#11 by Daniel Poveda Parrilla at Tue Feb 14 07:25:48 EST 2017

STATUS

editing

proposed

Discussion

Tue Feb 14

22:35

Charles R Greathouse IV: Thanks for the sequence -- I especially appreciate the illustration, they really help make sequences more understandable.

#10 by Daniel Poveda Parrilla at Tue Feb 14 07:23:54 EST 2017

FORMULA

a(n) = A282390(n+(n mod 2))*A000051(n-(n mod 2)) for n > 0.

a(n) = (A282390(n+(n mod 2)) - A000051(n-1+(n mod 2)))*A000051(n-(n mod 2)) + A028401(n+2) for n > 0.

STATUS

proposed

editing

Discussion

Tue Feb 14

07:25

Daniel Poveda Parrilla: Formulas valid only for n > 0 as offset of A282390 has changed.

#9 by Andrey Zabolotskiy at Tue Feb 14 03:51:11 EST 2017

STATUS

editing

proposed

#8 by Andrey Zabolotskiy at Tue Feb 14 03:42:23 EST 2017

DATA

4, 10, 25, 70, 238, 901, 3445, 13390, 52942, 210226, 838450, 3350725, 13393093, 53547790, 214151950, 856558645, 3426077749, 13703917774, 54815043790, 219258602290, 877031899954, 3508124454085, 14032487779525, 56129938535185, 224519713993489, 898078755310654

PROG

(Python)

m = [3, 1]

for i in range(25):

w, h = m[0], len(m)

print(sum(m)) # print(w) for widths of the polyminoes

m2 = [w-x for x in reversed(m) if w>x]

m = [w+x for x in m2] + [w for x in m if x==w] + m2

# Andrey Zabolotskiy, Feb 14 2017

KEYWORD

nonn,more,changed

STATUS

proposed

editing

#7 by Daniel Poveda Parrilla at Tue Feb 14 01:32:45 EST 2017

STATUS

editing

proposed