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A055066 Number of 7-covers of an unlabeled n-set. 8
1, 7, 62, 664, 8609, 127415, 2004975, 31500927, 474504448, 6708348262, 88249739792, 1078567590128, 12269901302433, 130370516668917, 1298891291366245, 12182760243381355, 107979270564656625, 907568508195185203, 7256984238345563764, 55365443728411530716, 404091280028746802188 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Number of 7 X n binary matrices with at least one 1 in every column up to row and column permutations. - Andrew Howroyd, Feb 28 2023
LINKS
PROG
(PARI) Vec(G(7, x)*(1-x) + O(x^40)) \\ G defined in A028657. - Andrew Howroyd, Feb 28 2023
CROSSREFS
Column 7 of A055080.
Sequence in context: A287481 A289212 A060005 * A216534 A167550 A304895
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Jun 12 2000
EXTENSIONS
a(0)=1 prepended by Alois P. Heinz, Aug 08 2022
Terms a(17) and beyond from Andrew Howroyd, Feb 28 2023
STATUS
approved

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Last modified March 28 16:58 EDT 2024. Contains 371254 sequences. (Running on oeis4.)