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A192512
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Number of ludic numbers (A003309) not greater than n.
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10
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1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 19
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
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FORMULA
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a(n) = #{A003309(k): 1<=k<=n} = Sum_{k=1..n} A192490(k).
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MATHEMATICA
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a3309[nmax_] := a3309[nmax] = Module[{t = Range[2, nmax], k, r = {1}}, While[Length[t] > 0, k = First[t]; AppendTo[r, k]; t = Drop[t, {1, -1, k}]]; r];
ludicQ[n_, nmax_] /; 1 <= n <= nmax := MemberQ[a3309[nmax], n];
nmax = 100;
b[n_] := Boole[ludicQ[n, nmax]];
Array[b, nmax] // Accumulate (* Jean-François Alcover, Dec 09 2021, after Ray Chandler in A003309 *)
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PROG
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(Haskell)
a192512 n = a192512_list !! (n-1)
a192512_list = scanl1 (+) $ map a192490 [1..]
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CROSSREFS
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Cf. A003309.
Cf. A192490 (first differences), A000720 (number of primes).
Sequence in context: A073047 A038567 A185195 * A036234 A061091 A350254
Adjacent sequences: A192509 A192510 A192511 * A192513 A192514 A192515
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KEYWORD
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nonn
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AUTHOR
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Reinhard Zumkeller, Jul 05 2011
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STATUS
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approved
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