A173958
Number A(n,k) of spanning trees in C_k X P_n; square array A(n,k), n>=1, k>=1, read by antidiagonals.
Original entry on oeis.org
1, 2, 1, 3, 12, 1, 4, 75, 70, 1, 5, 384, 1728, 408, 1, 6, 1805, 31500, 39675, 2378, 1, 7, 8100, 508805, 2558976, 910803, 13860, 1, 8, 35287, 7741440, 140503005, 207746836, 20908800, 80782, 1, 9, 150528, 113742727, 7138643400, 38720000000, 16864848000, 479991603, 470832, 1
Offset: 1
Square array A(n,k) begins:
1, 2, 3, 4, 5, ...
1, 12, 75, 384, 1805, ...
1, 70, 1728, 31500, 508805, ...
1, 408, 39675, 2558976, 140503005, ...
1, 2378, 910803, 207746836, 38720000000, ...
- Alois P. Heinz, Antidiagonals n = 1..60, flattened
- Germain Kreweras, Complexité et circuits Eulériens dans les sommes tensorielles de graphes, J. Combin. Theory, B 24 (1978), 202-212. See p. 210. - From _N. J. A. Sloane_, May 27 2012
- Eric Weisstein's World of Mathematics, Cycle Graph
- Eric Weisstein's World of Mathematics, Path Graph
- Wikipedia, Kirchhoff's theorem
Columns k=1-11 give:
A000012,
A001542,
A003690,
A003753,
A003733,
A158880,
A158898,
A210812,
A174001,
A210813,
A174089.
-
with(LinearAlgebra):
A:= proc(n, m) local M, i, j;
if m=1 then 1 else
M:= Matrix(n*m, shape=symmetric);
for i to n do
for j to m-1 do M[m*(i-1)+j, m*(i-1)+j+1]:=-1 od;
M[m*(i-1)+1, m*i]:= M[m*(i-1)+1, m*i]-1
od;
for i to n-1 do
for j to m do M[m*(i-1)+j, m*i+j]:=-1 od
od;
for i to n*m do
M[i,i]:= -add(M[i,j], j=1..n*m)
od;
Determinant(DeleteColumn(DeleteRow(M, 1), 1))
fi
end:
seq(seq(A(n, 1+d-n), n=1..d), d=1..9);
# Crude Maple program from N. J. A. Sloane, May 27 2012:
Digits:=200;
T:=(m,n)->round(Re(evalf(simplify(expand(
m*mul(mul( 4*sin(h*Pi/m)^2+4*sin(k*Pi/(2*n))^2, h=1..m-1), k=1..n-1))))));
# Alternative program using the resultant:
for n from 1 to 10 do seq(k*resultant(simplify((2*(ChebyshevT(k,(x + 2)/2) - 1))/x), simplify(ChebyshevU(n-1,1 - x/2)), x), k = 1 .. 10) end do; # Peter Bala, May 01 2014
-
t[m_, n_] := m*Product[Product[4*Sin[h*Pi/m]^2 + 4*Sin[k*Pi/(2*n)]^2, {h, 1, m-1}], {k, 1, n-1}]; Table[t[m, n-m+1] // Round, {n, 1, 9}, {m, n, 1, -1}] // Flatten (* Jean-François Alcover, Dec 05 2013, after N. J. A. Sloane *)
A158880
Number of spanning trees in C_6 X P_n.
Original entry on oeis.org
6, 8100, 7741440, 7138643400, 6551815840350, 6009209192448000, 5511006731579419434, 5054037303588059379600, 4634949992739663836897280, 4250612670512943969574312500, 3898145031429828405122837863554
Offset: 1
-
a:= n-> 6* (Matrix(1,18, (i,j)-> -sign(j-10) *[0, 1, 1350, 1290240, 1189773900, 1091969306725, 1001534865408000, 918501121929903239, 842339550598009896600, 772491665456610639482880][1+abs(j-10)]). Matrix(18, (i,j)-> if i=j-1 then 1 elif j=1 then [842608511100, -639641521152, 276457068288, -65829977967, 8292106368, -524839680, 16393554, -232704, 1152, -1][1+abs(i-9)] else 0 fi)^n) [1,10]: seq(a(n), n=1..15);
A158898
Number of spanning trees in C_7 X P_n.
Original entry on oeis.org
7, 35287, 113742727, 347251215703, 1050773495363767, 3174564739209417463, 9588099190533549457408, 28957256518828921149989143, 87453655435340440175476698487, 264117827347202707929587420182327
Offset: 1
-
a:= n-> 7* (Matrix([222727, 4031, 71, 1, 0, -1, -71, -4031]). Matrix(8, (i,j)-> if i=j-1 then 1 elif j=1 then [71, -952, 3976, -6384, 3976, -952, 71, -1][i] else 0 fi)^n)[1,5]^2: seq(a(n), n=1..15);
A174001
Number of spanning trees in C_9 X P_n.
Original entry on oeis.org
9, 632025, 23057815104, 763341471963225, 24743382596536452489, 797880028172050676793600, 25694231385152383926116001849, 827147402338052897443922764419225, 26625078176206788678765153788526329856
Offset: 1
-
a:= n-> 9* (Matrix([[0, 1, 265, 50616, 9209545, 1658090689, 297747101520, 53431400864569, 9586723471888105][1+abs(i)]$i=-7..8]). Matrix(16, (i, j)-> if i=j-1 then 1 elif j=1 then [[-427427424, 327381265, -146975161, 38357160, -5699687, 457655, -17736, 265, -1][1+abs(k)]$k=-7..8][i] else 0 fi)^n)[1, 8]^2: seq(a(n), n=1..20);
A174089
Number of spanning trees in C_11 X P_n.
Original entry on oeis.org
11, 10759331, 4435600730891, 1584603178322856659, 545701094921321191290251, 185861400461684004931359802019, 63080339061067311398935095930531419, 21384626538080492686675351682716886393459
Offset: 1
-
a:= n-> 11* (Matrix([[0, 1, 989, 635009, 379545563, 222731206721, 129986502957277, 75726985139241127, 44091461282285910613, 25667108238650778993721, 14940759758135641310394029, 8696803311384043382138568704, 5062251640287899331740697744283, 2946638531103878161891572927216367, 1715179927870529863091149494541065923, 998372029710787510889689081784904921409, 581132402632124482558541496059410958698763][1+abs(i)]*
signum(-i)$i=-15..16]). Matrix(32, (i, j)-> if i=j-1 then 1 elif j=1 then [[-9866686348925002518, 8584218556222705486, -5646220475933195574, 2797526034931937278, -1038052511465703094, 286230180847745070, -58096997326051905, 8585065341436957, -911803001143321, 68534901051869, -3574487862001, 125866549709, -2870938929, 39687581, -297177, 989, -1] [1+abs(k)]$k=-15..16][i] else 0 fi)^n)[1, 16]^2: seq(a(n), n=1..20);
A338832
Number of spanning trees in the k_1 X ... X k_j grid graph, where (k_1 - 1, ..., k_j - 1) is the partition with Heinz number n.
Original entry on oeis.org
1, 1, 1, 4, 1, 15, 1, 384, 192, 56, 1, 31500, 1, 209, 2415, 42467328, 1, 49766400, 1, 2558976, 30305, 780, 1, 3500658000000, 100352, 2911, 8193540096000, 207746836, 1, 76752081000, 1, 20776019874734407680, 380160, 10864, 4140081, 242716067758080000000, 1
Offset: 1
The partition (2, 2, 1) has Heinz number 18 and the 3 X 3 X 2 grid graph has a(18) = 49766400 spanning trees.
2 X n grid:
A001353(n) = a(2*prime(n-1))
3 X n grid:
A006238(n) = a(3*prime(n-1))
4 X n grid:
A003696(n) = a(5*prime(n-1))
5 X n grid:
A003779(n) = a(7*prime(n-1))
6 X n grid:
A139400(n) = a(11*prime(n-1))
7 X n grid:
A334002(n) = a(13*prime(n-1))
8 X n grid:
A334003(n) = a(17*prime(n-1))
9 X n grid:
A334004(n) = a(19*prime(n-1))
10 X n grid:
A334005(n) = a(23*prime(n-1))
n X n grid:
A007341(n) = a(prime(n-1)^2)
m X n grid:
A116469(m,n) = a(prime(m-1)*prime(n-1))
2 X 2 X n grid:
A003753(n) = a(4*prime(n-1))
2 X n X n grid:
A067518(n) = a(2*prime(n-1)^2)
n X n X n grid:
A071763(n) = a(prime(n-1)^3)
2 X ... X 2 grid:
A006237(n) = a(2^n)
Showing 1-6 of 6 results.
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