OFFSET
0,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..5000 (first 143 terms from Joerg Arndt)
Joerg Arndt, C++ program to compute this sequence, 2016
F. C. Auluck, On some new types of partitions associated with generalized Ferrers graphs, Proc. Cambridge Philos. Soc. 47, (1951), 679-686.
R. K. Guy, Letter to N. J. A. Sloane, Apr 08 1988 (annotated scanned copy, included with permission)
E. M. Wright, Stacks (III), Quart. J. Math. Oxford, 23 (1972), 153-158.
MAPLE
b:= proc(n, i, d) option remember; `if`(i*(i+1)/2<n, 0,
`if`(n=0, 1, b(n, i-1, d+1)+`if`(i>n, 0, d*b(n-i, i-1, 1))))
end:
a:= n-> b(n*(n-1)/2, n, 1):
seq(a(n), n=0..55); # Alois P. Heinz, Jul 08 2016
MATHEMATICA
b[n_, i_, d_] := b[n, i, d] = If[i*(i + 1)/2 < n, 0, If[n == 0, 1, b[n, i - 1, d + 1] + If[i > n, 0, d*b[n - i, i - 1, 1]]]];
a[n_] := b[n*(n - 1)/2, n, 1];
Table[a[n], {n, 0, 55}] (* Jean-François Alcover, Jul 28 2016, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn,nice
AUTHOR
EXTENSIONS
Edited by N. J. A. Sloane, Jun 20 2015
Terms a(0)..a(11) computed by R. K. Guy
Terms a(12)=56 and beyond from Joerg Arndt, Apr 10 2016
STATUS
approved