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 A224721 Number of (n+3) X 4 0..2 matrices with each 4 X 4 subblock idempotent. 1
 2052, 1623, 2471, 3506, 4257, 5737, 8117, 12306, 18187, 26561, 38040, 55162, 80519, 118413, 173641, 254339, 371847, 544345, 797402, 1169025, 1713358, 2510861, 3678903, 5391040, 7900541, 11579142, 16970092, 24870656, 36448737, 53417530 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-4) - 2*a(n-5) + 2*a(n-6) - 2*a(n-7) + a(n-8) for n>11. Empirical g.f.: x*(2052 - 4533*x + 3758*x^2 - 1090*x^3 - 2523*x^4 + 3494*x^5 - 3158*x^6 + 3203*x^7 - 1110*x^8 - 115*x^9 - 4*x^10) / ((1 - x)^2*(1 + x)*(1 - x + x^2)*(1 - x - x^3)). - Colin Barker, Sep 03 2018 EXAMPLE Some solutions for n=2: 1 1 0 2 1 1 2 0 1 2 2 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 1 1 0 1 1 0 0 0 0 0 0 2 0 1 1 2 2 1 0 0 0 0 CROSSREFS Column 1 of A224728. Sequence in context: A253711 A168176 A224728 * A224720 A320277 A322102 Adjacent sequences: A224718 A224719 A224720 * A224722 A224723 A224724 KEYWORD nonn AUTHOR R. H. Hardin, Apr 16 2013 STATUS approved

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Last modified December 7 11:26 EST 2023. Contains 367650 sequences. (Running on oeis4.)