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A224722 Number of (n+3) X 5 0..2 matrices with each 4 X 4 subblock idempotent. 1
1623, 1920, 2493, 2863, 3123, 4129, 5711, 7604, 9713, 12764, 17344, 23754, 32224, 43673, 59650, 81969, 112701, 154811, 212841, 293114, 404063, 557046, 767994, 1059140, 1461174, 2016107, 2781924, 3838807, 5297655, 7311353, 10090799 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) - a(n-2) + a(n-3) - 2*a(n-5) + a(n-6) - 2*a(n-7) + 2*a(n-8) + a(n-11) - a(n-12) for n>15.
Empirical g.f.: x*(1623 - 1326*x + 276*x^2 - 1826*x^3 - 2030*x^4 + 1499*x^5 - 70*x^6 + 3500*x^7 - 86*x^8 - 240*x^9 - 200*x^10 - 1693*x^11 + 508*x^12 + 48*x^13 + 5*x^14) / ((1 - x)^3*(1 + x)*(1 + x^2)*(1 + x + x^2)*(1 - x - x^4)). - Colin Barker, Sep 03 2018
EXAMPLE
Some solutions for n=2:
0 0 0 0 1 1 0 0 0 1 0 0 0 0 0 1 0 0 0 0
0 0 0 0 1 1 0 0 0 1 1 1 1 1 1 1 0 0 0 0
0 0 0 0 2 0 0 0 0 1 0 0 0 0 0 2 0 0 0 1
0 0 0 0 1 2 0 0 0 1 0 0 0 0 0 0 0 0 0 1
0 0 0 0 1 2 0 0 0 1 0 0 0 0 0 0 0 0 0 1
CROSSREFS
Column 2 of A224728.
Sequence in context: A269274 A020418 A347039 * A045288 A204726 A022060
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 16 2013
STATUS
approved

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Last modified June 17 02:48 EDT 2024. Contains 373432 sequences. (Running on oeis4.)