OFFSET
1,4
COMMENTS
Lengths of rows are 1 1 2 2 2 3 3 3 3 ... (A003056).
LINKS
P. A. MacMahon, Divisors of numbers and their continuations in the theory of partitions, Proc. London Math. Soc., 19 (1919), 75-113; Coll. Papers II, pp. 303-341.
FORMULA
T(n, k) = sum of (-1)^(k+s_1+s_2+...+s_k) * s_1*s_2*...*s_k where s_1, s_2, ..., s_k are such that s_1*m_1 + s_2*m_2 + ... + s_k*m_k = n and the sum is over all such k-partitions of n.
G.f. for k-th diagonal (the k-th row of the sideways triangle shown in the example): Sum_{ m_1 < m_2 < ... < m_k} q^(m_1+m_2+...+m_k)/((1+q^m_1)*(1+q^m_2)*...*(1+q^m_k))^2 = Sum_n T(n, k)*q^n.
EXAMPLE
Triangle turned on its side begins:
1 -1 4 -5 6 -4 8 -13 13 ...
1 -1 1 3 -2 1 -5 ...
1 -1 1 -2 ...
For example, T(8,3) = 1.
CROSSREFS
KEYWORD
sign,tabf,easy,nice
AUTHOR
N. J. A. Sloane, Mar 19 2001
EXTENSIONS
More terms from Naohiro Nomoto, Jan 24 2002
STATUS
approved