OFFSET
1,4
COMMENTS
The length of row n is A000041(n).
The (one part) Witt symmetric function w_n is defined in the links below. One should add w_0 = 1. It can be expressed in terms of the power sum symmetric functions p_k = Sum_{i>=1} (x_i)^k for the indeterminates {x_i}, by using the recurrence w_n = (1/n)*(p_n - Sum_{d|n,1 <= d < n} d*(w_d)^{n/d}), n >= 2, with w_1 = p_1.
In order to have integer coefficients n!*w_n is considered, and terms are listed in the Abramowitz-Stegun order (with rising number of parts).
A logarithmic generating function of the power sums is related to the {w_n}_{n>=1} sequence by Lp(t) := -Sum_{j>=1} p_j*(t^j)/j = log(Product_{n>=0} (1 - w_n*t^n)). See the links.
If only N indeterminates {x_i}_{i=1..N} are considered all coefficients corresponding to partitions with at least one part > N are set to 0 (in addition to the ones given in the sequence).
LINKS
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy]
H J. Borger, Witt vectors, semirings, and total positivity, arXiv:1310.3013 [math.CO], 2015, Section 4.5., pp. 295-296 [with theta -> w, psi-> p, and the n = 1..6 results on p. 295]
SAGE, Witt symmetric functions
FORMULA
w_n is given by the recurrence given in the comment above in terms of the power sum symmetric functions {p_i}_{i>=1}, for n >= 1.
T(n, k) gives the coefficient of (p_1)^{a(1,k)}*...*(p_n)^{a(n,k)} for n!*w_n, corresponding to the k-th partition of n in Abramowitz-Stegun order, written as 1^{a(1,k)}* ..*n^{a(n,k)}, with nonnegative integers a(n,j) satisfying Sum_{j=1..n} j*an,j) = n. The number of parts is Sum_{j=1..n} a(n,k) =: m(k).
EXAMPLE
The irregular triangle (partition array) begins:
n\k 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ...
---------------------------------------------------------------
1: 1
2: 1 -1
3: -2 0 -2
4: 6 0 -3 6 -9
5: 24 0 0 0 0 0 -24
6: 120 0 0 -40 0 0 -30 80 90 -90 -130
7: 720 0 0 0 0 0 0 0 0 0 0 0 0 0 -720
...
n = 8: 5040 0 0 0 -1260 0 0 0 1260 0 0 2520 3780 0 -945 3780 0 0 0 -6930 6300 -8505;
n = 9: 40320 0 0 0 0 0 0 0 0 0 0 -4480 0 0 0 0 0 0 0 0 13440 0 0 0 0 0 -13440 0 0 -35840;
n = 10: 362880 0 0 0 0 -725760 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -22680 145152 0 0 0 113400 0 0 -226800 0 226800 -113400 -412776;
...
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w_1 = p_1;
w_2 = (1/2)*(p_2 - (p_1)^2);
w_3 = (1/3!)*(2*p_3 + 0 - 2*(p_1)^3);
w_4 = (1/4!)*(6*p_4 + 0 - 3*(p_2)^2 + 6*(p_1)^2*p_2 - 9*(p_1)^4);
w_5 = (1/5!)*(24*p_5 + 0 + 0 + 0 + 0 + 0 - 24*(p_1)^5) = (1/5)*(p_5 - (p_1)^5);
w_6 = (1/6!)*(120*p_6 + 0 + 0 - 40*(p_3)^2 + 0 + 0 - 30*(p_2)^3 + 80*(p_1)^3*p_3 + 90*(p_1)^2*(p_2)^2 - 90*(p_1)^4*p_2 - 130*(p_1)^6)
= (1/72)*(12*p_6 - 4*(p_3)^2 - 3*(p_2)^3 + 8*(p_1)^3*p_3 + 9*(p_1)^2*(p_2)^2 - 9*(p_1)^4*p_2 - 13*(p_1)^6);
...
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CROSSREFS
KEYWORD
sign,tabf
AUTHOR
Wolfdieter Lang, Jun 05 2019
STATUS
approved