|
Search: id:A123237
|
|
| |
|
| 1, -1, -12, 144, 2400, -28224, -1296000, 50808384, 2434614000, -85975622656, -8396400230400, 691198592910336, 65694715632000000, -4784543769600000000, -796566295447796966400, 112616674749446400000000, 17805426854398997299200000, -2223594618178251399873232896
(list; graph; listen)
|
|
|
OFFSET
|
1,3
|
|
|
COMMENT
|
This neo-Hankel matrix type is symmetrical about the diagonal: The average (i*(j+1)/2+j*(i+1)/2)/4 =(i+j+2*i*j)/4 term is based on the sum of integers n(n+1)/2. I get Log plot fit of an exponent: Det[M[n]]=c*n^4.2586 a0 = Table[Det[Table[ If[i + j - 1 > m, 0, Floor[(i + j + 2*i*j)/4]], {i, 1, m}, {j, 1, m}]], {m, 3, 20}]; a = N[Log[Abs[%]]]; g1 = ListPlot[a, PlotJoined -> True]; y[x_] = Fit[a, {1, x}, x] g2 = Plot[y[x], {x, 0, 20}]; Show[{g1, g2}]
|
|
FORMULA
|
mij=If[i + j - 1 > m, 0, Floor[(i + j + 2*i*j)/4]]
|
|
MATHEMATICA
|
Table[Det[Table[If[i + j - 1 > m, 0, Floor[(i + j + 2*i*j)/4]], {i, 1, m}, {j, 1, m}]], {m, 1, 20}]
|
|
CROSSREFS
|
Cf. A000316.
Sequence in context: A001021 A000468 A076728 this_sequence A138444 A137886 A097303
Adjacent sequences: A123234 A123235 A123236 this_sequence A123238 A123239 A123240
|
|
KEYWORD
|
uned,sign
|
|
AUTHOR
|
Roger Bagula (rlbagulatftn(AT)yahoo.com), Oct 06 2006
|
|
|
Search completed in 0.002 seconds
|
