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A166812 Number of n X 7 1..2 arrays containing at least one of each value, all equal values connected, rows considered as a single number in nondecreasing order, and columns considered as a single number in nondecreasing order. 3
6, 34, 118, 328, 790, 1714, 3430, 6433, 11438, 19446, 31822, 50386, 77518, 116278, 170542, 245155, 346102, 480698, 657798, 888028, 1184038, 1560778, 2035798, 2629573, 3365854, 4272046, 5379614, 6724518, 8347678, 10295470, 12620254, 15380935, 18643558, 22481938 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
a(n) = A000580(n+7)-2. - Alois P. Heinz, May 31 2012
From G. C. Greubel, May 24 2016: (Start)
G.f.: 1/(1 - x)^8 - 2/(1-x).
E.g.f.: (1/7!)*(-5040 + 35280*x + 52920*x^2 + 29400*x^3 + 7350*x^4 + 882*x^5 + 49*x^6 + x^7)*exp(x). (End)
EXAMPLE
Some solutions for n=4
...1.1.1.1.2.2.2...1.1.1.1.2.2.2...1.1.1.1.1.1.1...1.1.1.1.1.1.2
...1.1.1.2.2.2.2...1.1.2.2.2.2.2...1.1.1.1.2.2.2...1.1.1.1.1.1.2
...1.2.2.2.2.2.2...1.1.2.2.2.2.2...1.1.2.2.2.2.2...1.1.1.2.2.2.2
...1.2.2.2.2.2.2...1.2.2.2.2.2.2...1.2.2.2.2.2.2...1.2.2.2.2.2.2
------
...1.1.1.1.1.1.2...1.1.1.1.1.1.2...1.1.1.1.1.2.2...1.1.1.1.1.2.2
...1.1.1.2.2.2.2...1.1.1.1.1.2.2...1.1.1.1.1.2.2...1.1.1.2.2.2.2
...1.1.2.2.2.2.2...1.2.2.2.2.2.2...1.1.1.2.2.2.2...1.2.2.2.2.2.2
...2.2.2.2.2.2.2...2.2.2.2.2.2.2...1.1.1.2.2.2.2...2.2.2.2.2.2.2
MAPLE
a:= n-> binomial(n+7, 7)-2:
seq(a(n), n=1..50); # Alois P. Heinz, May 31 2012
MATHEMATICA
Table[Binomial[n+7, 7] -2, {n, 1, 100}] (* G. C. Greubel, May 24 2016 *)
CROSSREFS
Sequence in context: A061616 A368757 A222308 * A262844 A166941 A086934
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 21 2009
STATUS
approved

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Last modified March 28 10:31 EDT 2024. Contains 371240 sequences. (Running on oeis4.)