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A287376 Array read by antidiagonals: T(m,n) = number of independent vertex sets in the complete prism graph K_m X C_n. 8

%I #10 Jun 06 2017 11:54:35

%S 1,3,1,4,7,1,7,13,13,1,11,35,34,21,1,18,81,121,73,31,1,29,199,391,325,

%T 136,43,1,47,477,1300,1361,731,229,57,1,76,1155,4285,5781,3771,1447,

%U 358,73,1,123,2785,14161,24473,19606,8881,2605,529,91,1

%N Array read by antidiagonals: T(m,n) = number of independent vertex sets in the complete prism graph K_m X C_n.

%C Equivalently, the number of 0..m words of length n with cyclically adjacent letters unequal with the exception that 0's may be adjacent.

%H Andrew Howroyd, <a href="/A287376/b287376.txt">Table of n, a(n) for n = 1..1275</a>

%F Row g.f.: ((m+1)-(m^2-2)*x-(2*m-1)*x^2)/(1-(m-1)*x-(m+1)*x^2-x^3).

%e Table starts:

%e ====================================================

%e m\n| 1 2 3 4 5 6 7 8

%e ---|------------------------------------------------

%e 1 | 1 3 4 7 11 18 29 47 ...

%e 2 | 1 7 13 35 81 199 477 1155 ...

%e 3 | 1 13 34 121 391 1300 4285 14161 ...

%e 4 | 1 21 73 325 1361 5781 24473 103685 ...

%e 5 | 1 31 136 731 3771 19606 101781 528531 ...

%e 6 | 1 43 229 1447 8881 54763 337429 2079367 ...

%e 7 | 1 57 358 2605 18551 132504 946037 6754805 ...

%e 8 | 1 73 529 4361 35361 287305 2333745 18957321 ...

%e ...

%t max = 10; row[m_] := ((m+1) - (m^2 - 2)*x - (2*m - 1)*x^2)/(1 - (m-1)*x - (m+1)*x^2 - x^3) + O[x]^(max+1) // CoefficientList[#, x]& // Rest;

%t T = Table[row[m], {m, 1, max}];

%t Table[T[[m-n+1, n]], {m, 1, max}, {n, m, 1, -1}] // Flatten (* _Jean-François Alcover_, Jun 06 2017 *)

%o (PARI)

%o RowGf(m,x)=((m+1)-(m^2-2)*x-(2*m-1)*x^2)/(1-(m-1)*x-(m+1)*x^2-x^3);

%o for (m=1,8,for(n=1,8,print1(Vec(RowGf(m,x)+O(x^(n+1)))[n+1], " "));print);

%Y Rows 2-7 are A051927, A051928, A051929, A051930, A051931, A051932.

%Y Cf. A135597 (K_m X P_n), A106512, A175243.

%K nonn,tabl

%O 1,2

%A _Andrew Howroyd_, May 23 2017

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Last modified April 18 10:01 EDT 2024. Contains 371779 sequences. (Running on oeis4.)