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A236935 The infinite Seidel matrix H read by antidiagonals upwards; H = (H(n,k): n,k >= 0). 2
1, 0, -1, -1, -1, 0, 0, 1, 2, 2, 5, 5, 4, 2, 0, 0, -5, -10, -14, -16, -16, -61, -61, -56, -46, -32, -16, 0, 0, 61, 122, 178, 224, 256, 272, 272, 1385, 1385, 1324, 1202, 1024, 800, 544, 272, 0, 0, -1385, -2770, -4094, -5296, -6320, -7120, -7664, -7936, -7936, -50521, -50521, -49136, -46366, -42272, -36976, -30656, -23536, -15872, -7936, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,9

COMMENTS

This is, in essence, a signed version of the triangle in A008280.

LINKS

Table of n, a(n) for n=0..65.

D. Dumont and G. Viennot, A combinatorial interpretation of the Seidel generation of Genocchi numbers, Preprint, Annotated scanned copy.

D. Dumont and G. Viennot, A combinatorial interpretation of the Seidel generation of Genocchi numbers, Annals of Discrete Mathematics, 6 (1980), 77-87.

Dominique Foata and Guo-Niu Han, Seidel Triangle Sequences and Bi-Entringer Numbers, November 20, 2013.

Dominique Foata and Guo-Niu Han, Seidel Triangle Sequences and Bi-Entringer Numbers, European Journal of Combinatorics, 42 (2014), 243-260.

L. Seidel, Über eine einfache Entstehungsweise der Bernoullischen Zahlen und einiger verwandten Reihen, Sitzungsberichte der mathematisch-physikalischen Classe der königlich bayerischen Akademie der Wissenschaften zu München, Vol. 7 (1877), pp. 157-187; see Beilage 4 (p. 187).

FORMULA

From Petros Hadjicostas, Feb 20 2021: (Start)

H(n,0) = A122045(n).

H(0,k) = (-1)^n*A155585(n).

H(n,k) = Sum_{i=0..n} binomial(n,i)*H(0,k+i).

H(n,k) = Sum_{i=0..k} (-1)^i*binomial(k,i)*H(n+k-i,0).

H(n,n) = A099023(n).

Bivariate e.g.f.: Sum_{n,k>=0} H(n,k)*(x^n/n!)*(y^k/k!) = 2*exp(x)/(1 + exp(2*(x+y))).

H(n,k) = (-1)^(n+k)*A239005(n+k,k), where the latter is a triangle.

H(n,k) = -A008280(n+k,k) if ((n+k) mod 4) == 1 or 2, and H(n,k) = A008280(n+k,k) if ((n+k) mod 4) == 3 or 0, provided A008280 is read as a triangle. (End)

EXAMPLE

Array begins:

     1   -1    0    2    0 -16   0 272 0 ...

     0   -1    2    2  -16 -16 272 272 ...

    -1    1    4  -14  -32 256 544 ...

     0    5  -10  -46  224 800 ...

     5   -5  -56  178 1024 ...

     0  -61  122 1202 ...

   -61   61 1324 ...

     0 1385 ...

  1385 ...

  ...

PROG

(PARI) a(n) = 2^n*2^(n+1)*(subst(bernpol(n+1, x), x, 3/4) - subst(bernpol(n+1, x), x, 1/4))/(n+1) /* A122045 */

H(n, k) = sum(i=0, k, (-1)^i*binomial(k, i)*a(n+k-i)) /* Petros Hadjicostas, Feb 21 2021 */

/* Second PARI program (same a(n) for A122045 as above) */

H(n, k) = (-1)^(n+k)*sum(i=0, k, binomial(k, i)*a(n+i)) /* Petros Hadjicostas, Feb 21 2021 */

CROSSREFS

Cf. A008280, A099023, A122045, A155585, A239005.

Sequence in context: A257943 A008280 A239005 * A213187 A317921 A195710

Adjacent sequences:  A236932 A236933 A236934 * A236936 A236937 A236938

KEYWORD

sign,tabl

AUTHOR

N. J. A. Sloane, Feb 17 2014

EXTENSIONS

More terms from Petros Hadjicostas, Feb 21 2021

STATUS

approved

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Last modified July 29 17:41 EDT 2021. Contains 346346 sequences. (Running on oeis4.)