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 A180684 a(n) equals the sum of path counts in the (right-aligned Ferrers plots of) the partitions of n. 1
 1, 2, 3, 6, 9, 18, 27, 49, 77, 129, 199, 329, 497, 787, 1194, 1838, 2738, 4154, 6108, 9098, 13265, 19432, 28024, 40612, 57961, 82958, 117469, 166390, 233520, 327899, 456534, 635503, 878657, 1213450, 1666138, 2285105, 3117131, 4246399, 5758532 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Also equals row sums of A180683. LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..100. MATHEMATICA pathcount[p_] := Block[{ferr = (0*Range[#1] &) /@ p}, Last[ Fold[ Rest[ FoldList[ Plus, 0, Drop[#1, Length[#1] - Length[#2]] + #2]] &, 1 + First[ferr], Rest[ferr]]]]; f[n_] := Block[{k = 1, s = 0}, While[k < n + 1, s = s + Plus @@ pathcount /@ IntegerPartitions[n, {k}]; k++ ]; s]; Array[f, 39] CROSSREFS Cf. A180683 Sequence in context: A261661 A062865 A351018 * A206100 A178940 A018264 Adjacent sequences: A180681 A180682 A180683 * A180685 A180686 A180687 KEYWORD nonn AUTHOR Wouter Meeussen, Sep 16 2010 EXTENSIONS a(37) onwards from Robert G. Wilson v, Sep 25 2010 STATUS approved

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Last modified September 27 05:14 EDT 2023. Contains 365674 sequences. (Running on oeis4.)