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”).

A057094
Coefficient triangle for certain polynomials (rising powers).
1
0, 0, -1, 0, 0, -1, 0, 0, 1, -1, 0, 0, 0, 2, -1, 0, 0, 0, -1, 3, -1, 0, 0, 0, 0, -3, 4, -1, 0, 0, 0, 0, 1, -6, 5, -1, 0, 0, 0, 0, 0, 4, -10, 6, -1, 0, 0, 0, 0, 0, -1, 10, -15, 7, -1, 0, 0, 0, 0, 0, 0, -5, 20, -21, 8, -1, 0, 0, 0, 0, 0, 0, 1, -15, 35, -28, 9, -1, 0, 0, 0, 0, 0, 0, 0, 6, -35, 56, -36, 10, -1, 0, 0, 0, 0, 0, 0, 0, -1, 21, -70, 84
OFFSET
0,14
COMMENTS
The row polynomials p(n,x) := sum(a(n,m)*x^m,m=0..n) are negative scaled Chebyshev U-polynomials: p(n,x)= -U(n-1,sqrt(x)/2)*(sqrt(x))^(n+1), n >= 1. p(0,x)=0. p(n-1,1/x) appears in the n-th power of the g.f. of Catalan's numbers A000108, c(x): (c(x))^n = p(n-1,1/x)*1 -p(n,1/x)*x*c(x). Cf. Lang reference eqs.(1) and (2).
Signed version of A284938. - Eric W. Weisstein, Apr 06 2017
FORMULA
a(n, m)=0 if n<m; a(0, 0)=0; a(n, m)= ((-1)^(n-m+1))*binomial(m-1, n-m) if n >= 1 and n >= m >=floor(n/2)+1; else 0.
EXAMPLE
Triangle begins:
0;
0, -1;
0, 0, -1;
0, 0, 1, -1;
0, 0, 0, 2, -1;
0, 0, 0, -1, 3, -1;
...
MATHEMATICA
Prepend[CoefficientList[Table[I^n x^(n/2) Fibonacci[n - 1, -I Sqrt[x]], {n, 2, 14}], x], {0}] // Flatten (* Eric W. Weisstein, Apr 06 2017 *)
Prepend[CoefficientList[Table[-x^(n/2) ChebyshevU[n - 2, Sqrt[x]/2], {n, 2, 14}], x], {0}] // Flatten (* Eric W. Weisstein, Apr 06 2017 *)
PROG
(PARI) tabl(nn) = {for (n=0, nn, for (k=0, n, if ((n==0) || (k < n\2+1), v = 0, v = (-1)^(n-k+1)*binomial(k-1, n-k)); print1(v, ", "); ); print(); ); } \\ Michel Marcus, Jan 14 2016
CROSSREFS
Cf. A284938 (unsigned version).
Sequence in context: A022909 A292136 A032239 * A284938 A186084 A301345
KEYWORD
easy,sign,tabl
AUTHOR
Wolfdieter Lang, Aug 11 2000
STATUS
approved