The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A294151 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A294151

Number of perforated polyominoes with n cells, identifying mirror images.
(history; published version)

#9 by Joerg Arndt at Wed Dec 13 04:03:52 EST 2023

STATUS

editing

approved

#8 by Joerg Arndt at Mon Dec 11 09:29:01 EST 2023

DATA

1, 1, 2, 3, 8, 13, 36, 76, 202, 482, 1281, 3277, 8749, 23083, 62056, 166498, 450576, 1220542, 3321870, 9057388, 24769906

EXTENSIONS

a(16) - a(21) from Joerg Arndt, Dec 11 2023

STATUS

approved

editing

#7 by Peter Luschny at Mon Oct 30 18:17:00 EDT 2017

STATUS

reviewed

approved

#6 by Andrey Zabolotskiy at Wed Oct 25 08:16:28 EDT 2017

STATUS

proposed

reviewed

#5 by Michel Marcus at Tue Oct 24 01:34:39 EDT 2017

STATUS

editing

proposed

Discussion

Tue Oct 24

08:03

George Sicherman: O.K.  Thank you.

#4 by Michel Marcus at Tue Oct 24 01:34:26 EDT 2017

NAME

Number of perforated polyominoes with N n cells, identifying mirror images.

STATUS

proposed

editing

Discussion

Tue Oct 24

01:34

Michel Marcus: n is the usual index

#3 by George Sicherman at Mon Oct 23 22:55:03 EDT 2017

STATUS

editing

proposed

#2 by George Sicherman at Mon Oct 23 22:54:43 EDT 2017

NAME

allocated for George SichermanNumber of perforated polyominoes with N cells, identifying mirror images.

DATA

1, 1, 2, 3, 8, 13, 36, 76, 202, 482, 1281, 3277, 8749, 23083, 62056

OFFSET

1,3

COMMENTS

A perforated polyomino is a polyomino in which every cell has at least one even coordinate.

EXAMPLE

a(4)=3 because there are 5 tetrominoes, and the skew and square tetrominoes do not lie in the perforated grid, which leaves 3.

CROSSREFS

Cf. A000105, number of polyominoes with n cells; A292065, number of Besźel Polycubes with n cells, distinguishing mirror images; A292157, same but identifying mirror images.

KEYWORD

allocated

nonn,more,hard

AUTHOR

George Sicherman, Oct 23 2017

STATUS

approved

editing

#1 by George Sicherman at Mon Oct 23 22:54:43 EDT 2017

NAME

allocated for George Sicherman

KEYWORD

allocated

STATUS

approved