

A192512


Number of ludic numbers (A003309) not greater than n.


10



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
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OFFSET

1,2


LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000


FORMULA

a(n) = #{A003309(k): 1<=k<=n} = Sum_{k=1..n} A192490(k).


MATHEMATICA

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 (* JeanFrançois Alcover, Dec 09 2021, after Ray Chandler in A003309 *)


PROG

(Haskell)
a192512 n = a192512_list !! (n1)
a192512_list = scanl1 (+) $ map a192490 [1..]


CROSSREFS

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


KEYWORD

nonn


AUTHOR

Reinhard Zumkeller, Jul 05 2011


STATUS

approved



