[go: up one dir, main page]

login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A157784
Triangle read by rows: the coefficient [x^k] of the polynomial Product_{i=1..n} (4^(i-1)-x), in row n and column 0 <= k <= n.
3
1, 1, -1, 4, -5, 1, 64, -84, 21, -1, 4096, -5440, 1428, -85, 1, 1048576, -1396736, 371008, -23188, 341, -1, 1073741824, -1431306240, 381308928, -24115520, 372372, -1365, 1, 4398046511104, -5863704100864, 1563272675328, -99158478848
OFFSET
0,4
COMMENTS
Row sums except n=0 are zero.
The matrix inverses seem to be related to the Gaussian q-form combinations.
Triangle T(n,k), 0 <= k <= n, read by rows given by [1,q-1,q^2,q^3-q,q^4,q^5-q^2,q^6,q^7-q^3,q^8,...] DELTA [ -1,0,-q,0,-q^2,0,-q^3,0,-q^4,0,...] (for q=4)=[1,3,16,60,256,1008,4096,16320,65536,261888,...] DELTA [ -1,0,-4,0,-16,0,-64,0,-256,0,-1024,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 10 2009
EXAMPLE
Triangle begins
1;
1, -1;
4, -5, 1;
64, -84, 21, -1;
4096, -5440, 1428, -85, 1;
1048576, -1396736, 371008, -23188, 341, -1;
1073741824, -1431306240, 381308928, -24115520, 372372, -1365, 1;
4398046511104, -5863704100864, 1563272675328, -99158478848, 1549351232, -5963412, 5461, -1;
72057594037927936, -96075326035066880, 25618523216674816, -1626175790120960, 25483729063936, -99253893440, 95436436, -21845, 1;
Row n=3 represents 64 - 84*x + 21*x^2 - x^3.
MAPLE
A157784 := proc(n, k)
product( 4^(i-1)-x, i=1..n) ;
coeftayl(%, x=0, k) ;
end proc: # R. J. Mathar, Oct 15 2013
MATHEMATICA
Clear[f, q, M, n, m];
q = 4;
f[k_, m_] := If[k == m, q^(n - k), If[m == 1 && k < n, q^(n - k), If[k == n && m == 1, -(n-1), If[k == n && m > 1, 1, 0]]]];
M[n_] := Table[f[k, m], {k, 1, n}, {m, 1, n}];
Table[M[n], {n, 1, 10}];
Join[{1}, Table[Expand[CharacteristicPolynomial[M[n], x]], {n, 1, 7}]];
a = Join[{{ 1}}, Table[CoefficientList[CharacteristicPolynomial[M[n], x], x], {n, 1, 7}]];
Flatten[a]
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Roger L. Bagula, Mar 06 2009
STATUS
approved