A192490 Characteristic function of ludic numbers (A003309).

1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0

Offset

1

Comments

a(A003309(n)) = 1 and a(A192607(n)) = 0.

Links

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

Index entries for characteristic functions

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;
a[n_] := Boole[ludicQ[n, nmax]];
Array[a, nmax] (* Jean-François Alcover, Dec 09 2021, after Ray Chandler in A003309 *)

Prog

(Haskell) a192490 n = a192490_list !! (n-1)
a192490_list = ch [1..] a003309_list where
   ch (i:is) ls'@(l:ls) = if i == l then 1 : ch is ls else 0 : ch is ls'
-- Reinhard Zumkeller, Feb 10 2014, Jul 05 2011

Crossrefs

Cf. A192512 (partial sums).

Sequence in context: A336868 A083187 A187036 * A267133 A080339 A294905

Adjacent sequences: A192487 A192488 A192489 * A192491 A192492 A192493

Keyword

nonn

Author

Reinhard Zumkeller, Jul 05 2011

Status

approved