A006380 - OEIS

A006380

Number of equivalence classes of 4 X n binary matrices when one can permute rows, permute columns and complement columns.
(Formerly M2735)

1, 3, 8, 19, 41, 81, 153, 273, 468, 774, 1240, 1930, 2933, 4356, 6341, 9064, 12743, 17643, 24093, 32479, 43270, 57019, 74377, 96103, 123089, 156354, 197081, 246622, 306519, 378520, 464614, 567028, 688276, 831169, 998845, 1194793, 1422899, 1687447, 1993182

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

REFERENCES

M. A. Harrison, On the number of classes of binary matrices, IEEE Trans. Computers, 22 (1973), 1048-1051.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Andrew Howroyd, Table of n, a(n) for n = 0..1000

M. A. Harrison, On the number of classes of binary matrices, IEEE Transactions on Computers, C-22.12 (1973), 1048-1052. (Annotated scanned copy)

Index entries for sequences related to binary matrices

Index entries for linear recurrences with constant coefficients, signature (4,-5,2,-2,2,5,-8,6,-8,5,2,-2,2,-5,4,-1).

FORMULA

G.f.: (1 - x + x^2 + x^4 + x^6 - x^7 + x^8)/((1 - x)^8*(1 + x)^2*(1 + x^2)*(1 + x + x^2)^2). - Andrew Howroyd, May 30 2023

PROG

(PARI) Vec((1 - x + x^2 + x^4 + x^6 - x^7 + x^8)/((1 - x)^8*(1 + x)^2*(1 + x^2)*(1 + x + x^2)^2) + O(x^41)) \\ Andrew Howroyd, May 30 2023

CROSSREFS

Row n=4 of A363349.

Cf. A000601, A006148, A006383.

Sequence in context: A082535 A007326 A136396 * A328540 A260547 A328541

Adjacent sequences: A006377 A006378 A006379 * A006381 A006382 A006383

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

Terms a(7) onwards from Max Alekseyev, Feb 05 2010

STATUS

approved