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Search: a370965 -id:a370965
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a(n) = number of "lonesum" 2 X 2 X n tensors.
+10
3
1, 14, 104, 644, 3668, 19964, 105764, 550844, 2836868, 14498204, 73695524, 373141244, 1883894468, 9490820444, 47735267684, 239788294844, 1203351134468, 6034279718684, 30241150798244, 151483730475644, 758527460524868, 3797063240264924, 19002992063903204
OFFSET
0,2
FORMULA
From Filip Stappers, Aug 27 2024: (Start)
a(n) = 8*5^n - 4*4^n - 4*3^n + 2^n.
G.f.: (1-21*z^2-28*z^3)/((1-5*z)*(1-4*z)*(1-3*z)*(1-2*z)). (End)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 04 2024
EXTENSIONS
a(7) from Michael S. Branicky, Apr 05 2024
a(8) from Michael S. Branicky, Apr 06 2024
a(9) from Michael S. Branicky, Apr 08 2024
a(10) from Michael S. Branicky, Apr 27 2024
a(0) and more terms from Filip Stappers, Aug 27 2024
STATUS
approved
a(n) = number of "lonesum" n X n X n tensors.
+10
3
2, 104, 126164
OFFSET
1,1
LINKS
CROSSREFS
KEYWORD
nonn,more,bref
AUTHOR
N. J. A. Sloane, Apr 04 2024
STATUS
approved
a(n) = number of "weakly lonesum" 2 X 2 X n tensors.
+10
3
1, 16, 254, 4006, 62834, 980926, 15251714, 236305246, 3649992194, 56225671966, 864046126274, 13249946549086, 202798763405954, 3098675363464606, 47273845225223234, 720219685203906526, 10958863373616410114, 166560903942055522846, 2528904905860164038594
OFFSET
0,2
FORMULA
From Filip Stappers, Aug 25 2024: (Start)
a(n) = 2*15^n - 14^n.
G.f.: (1-13*z) / ((1-15*z)*(1-14*z)). (End)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Apr 04 2024
EXTENSIONS
a(7) from Michael S. Branicky, Apr 07 2024
a(0) and more terms from Filip Stappers, Aug 25 2024
STATUS
approved

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