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A100482
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a(1) = 1 thereafter a(n) = Sum_{k=1..n-1} ceiling(a(n-k)/k).
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2
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1, 1, 2, 4, 7, 12, 21, 34, 55, 88, 143, 227, 361, 572, 908, 1439, 2279, 3607, 5709, 9033, 14294, 22615, 35779, 56605, 89551, 141671, 224123, 354561, 560908, 887349, 1403769, 2220732, 3513150, 5557727, 8792198, 13909056, 22003809, 34809516
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OFFSET
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1,3
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LINKS
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MAPLE
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a[1]:=1: for n from 2 to 40 do a[n]:=sum(ceil(a[n-k]/k), k=1..n-1) od:seq(a[n], n=1..40);
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MATHEMATICA
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a[n_]:= a[n]= If[n==1, 1, Sum[Ceiling[a[n-k]/k], {k, n-1}]];
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PROG
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(SageMath)
@CachedFunction
if (n==1): return 1
else: return sum( ((a(n-k)+k-1)//k) for k in range(1, n) )
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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