OFFSET
0,5
COMMENTS
Matrix inverse of A109449, the unsigned version of this sequence. More precisely, consider both of these triangles as the nonzero lower left of an infinite square array / matrix, filled with zeros above/right of the diagonal. Then these are mutually inverse of each other; in matrix notation: A247453 . A109449 = A109449 . A247453 = Identity matrix. In more conventional notation, for any m,n >= 0, Sum_{k=0..n} A247453(n,k)*A109449(k,m) = Sum_{k=0..n} A109449(n,k)*A247453(k,m) = delta(m,n), the Kronecker delta (= 1 if m = n, 0 else). - M. F. Hasler, Oct 06 2017
LINKS
Reinhard Zumkeller, Rows n = 0..125 of table, flattened
Peter Luschny, An old operation on sequences: the Seidel transform
J. Millar, N. J. A. Sloane and N. E. Young, A new operation on sequences: the Boustrophedon transform, J. Combin. Theory, 17A 44-54 1996 (Abstract, pdf, ps).
OEIS Wiki, Boustrophedon transform.
Wikipedia, Boustrophedon transform
FORMULA
EXAMPLE
. 0: 1
. 1: -1 1
. 2: 1 -2 1
. 3: -2 3 -3 1
. 4: 5 -8 6 -4 1
. 5: -16 25 -20 10 -5 1
. 6: 61 -96 75 -40 15 -6 1
. 7: -272 427 -336 175 -70 21 -7 1
. 8: 1385 -2176 1708 -896 350 -112 28 -8 1
. 9: -7936 12465 -9792 5124 -2016 630 -168 36 -9 1
. 10: 50521 -79360 62325 -32640 12810 -4032 1050 -240 45 -10 1 .
MATHEMATICA
a111[n_] := n! SeriesCoefficient[(1+Sin[x])/Cos[x], {x, 0, n}];
T[n_, k_] := (-1)^(n-k) Binomial[n, k] a111[n-k];
Table[T[n, k], {n, 0, 10}, {k, 0, n}] // Flatten (* Jean-François Alcover, Aug 03 2018 *)
PROG
(Haskell)
a247453 n k = a247453_tabl !! n !! k
a247453_row n = a247453_tabl !! n
a247453_tabl = zipWith (zipWith (*)) a109449_tabl a097807_tabl
(PARI) A247453(n, k)=(-1)^(n-k)*binomial(n, k)*if(n>k, 2*abs(polylog(k-n, I)), 1) \\ M. F. Hasler, Oct 06 2017
CROSSREFS
KEYWORD
sign,tabl
AUTHOR
Reinhard Zumkeller, Sep 17 2014
EXTENSIONS
Edited by M. F. Hasler, Oct 06 2017
STATUS
approved