cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A355540 Triangle read by rows. Row n gives the coefficients of Product_{k=0..n} (x - k!) expanded in decreasing powers of x, with row 0 = {1}.

Original entry on oeis.org

1, 1, -1, 1, -2, 1, 1, -4, 5, -2, 1, -10, 29, -32, 12, 1, -34, 269, -728, 780, -288, 1, -154, 4349, -33008, 88140, -93888, 34560, 1, -874, 115229, -3164288, 23853900, -63554688, 67633920, -24883200, 1, -5914, 4520189, -583918448, 15971865420, -120287210688, 320383261440, -340899840000, 125411328000
Offset: 0

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Author

Thomas Scheuerle, Jul 06 2022

Keywords

Comments

Essentially the same as A136457 with rows in reversed order.
Let M be an n X n matrix filled by Bell numbers A000110(j+k-2) with rows and columns j = 1..n, k = 1..n; then its determinant equals unsigned T(n, n). If we use A000110(j+k), the determinant will equal unsigned T(n+1, n). Can we find a general formula for T(n+m, n) based on determinants of matrices and Bell numbers?

Examples

			The triangle begins:
  1;
  1,   -1;
  1,   -2,      1;
  1,   -4,      5,       -2;
  1,  -10,     29,      -32,       12;
  1,  -34,    269,     -728,      780,      -288;
  1, -154,   4349,   -33008,    88140,    -93888,    34560;
  1, -874, 115229, -3164288, 23853900, -63554688, 67633920, -24883200;
  ...
Row 4: x^4 - 10*x^3 + 29*x^2 - 32*x + 12 = (x-0!)*(x-1!)*(x-2!)*(x-3!).
Illustration of T(1 to 5,1) as tree structure:
.
. o        o         o            o                         o
.          o         o            o                         o
.                   o o          o o                       o o
.                              ooo ooo                   ooo ooo
.                                             oooo oooo oooo oooo oooo oooo
. 1 +1 =   2 +2 =    4 +2*3 =     10 +6*4 =                 34
.
Illustration of T(2 to 4,2) as tree structure:
.
. o         o              -----o-----
.        o     o          o           o
.        o     o       ---o---     ---o---
.                     o   o   o   o   o   o
.                     o   o   o   o   o   o
.                    o o o o o o o o o o o o
. 1 +2*2 =  5 +6*4 =            29
.
Illustration of T(3 to 4,3) as tree structure:
.            ------------
. oo     ---o---      ---o---
.       o   o   o    o   o   o
.      o o o o o o  o o o o o o
.      o o o o o o  o o o o o o
.  2  +6*5 =      32
		

Crossrefs

Cf. A008276 (The Stirling numbers of the first kind in reverse order).
Cf. A039758 (Coefficients for polynomials with roots in odd numbers).
Cf. A349226 (Coefficients for polynomials with roots in x^x).

Programs

  • PARI
    T(n, k) = polcoeff(prod(m=0, n-1, (x-m!)), n-k);

Formula

T(n, 0) = 1.
T(n, 1) = -A003422(n).
T(n, 2) = Sum_{m=0..n-1} !m*m!.
T(n, k) = Sum_{m=0..n-1} -T(m, k-1)*m!.
T(n, n) = (-1)^n*A000178(n).
T(n, n-1) = -(-1)^n*A203227(n), for n > 0.
T(n+1, n) = (-1)^n*A000178(n)*A000522(n).
Sum_{m=0..k} T(n, k) = 0, for n > 0.
Sum_{m=0..k} abs(T(n, k)) = A217757(n+1).
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