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 A005575 a(n) = A259095(2n,n). (Formerly M1390) 7
 0, 0, 1, 2, 5, 11, 20, 37, 63, 110, 174, 283, 435, 671, 1001, 1492, 2160, 3127, 4442, 6269, 8739, 12109, 16597, 22618, 30576, 41077, 54834, 72788, 96056, 126131, 164829, 214327, 277534, 357810, 459507, 587779, 749220, 951473, 1204501, 1519691, 1911618, 2397247, 2997985, 3738482, 4649981, 5768457, 7138640, 8812704, 10854735, 13339286 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS Computed by R. K. Guy in 1988. 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 = 1..900 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)/2n, 0, d*b(n-i, i-1, 1))))     end: a:= n-> b(n, n-1, 1): seq(a(n), n=1..50);  # 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, 1]; Table[a[n], {n, 1, 50}] (* Jean-François Alcover, Jul 28 2016, after Alois P. Heinz *) CROSSREFS Cf. A259095, A005576, A005577. Sequence in context: A022908 A256310 A026390 * A050407 A113032 A100134 Adjacent sequences:  A005572 A005573 A005574 * A005576 A005577 A005578 KEYWORD nonn,nice AUTHOR EXTENSIONS Edited by N. J. A. Sloane, Jun 20 2015 Terms a(25) and beyond from Joerg Arndt, Apr 09 2016 STATUS approved

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