A192505 Non-ludic numbers that are prime numbers.

19, 31, 59, 73, 79, 101, 103, 109, 113, 137, 139, 151, 163, 167, 191, 197, 199, 229, 241, 251, 263, 269, 271, 281, 293, 311, 317, 347, 349, 367, 373, 379, 401, 409, 439, 443, 449, 457, 461, 479, 487, 491, 499, 521, 523, 547, 557, 563, 569, 571, 587, 599, 601

Offset: 1

Author

Reinhard Zumkeller, Jul 05 2011

Keywords

• nonn

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

Crossrefs

Intersection of A000040 and A192607.

Cf. A010051, A192490.

Programs

Haskell

a192505 n = a192505_list !! (n-1)
a192505_list = filter ((== 1) . a010051) a192607_list

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];
terms = 1000;
f[nmax_] := f[nmax] = Select[Range[nmax], !ludicQ[#, nmax] && PrimeQ[#]&] // PadRight[#, terms]&;
f[nmax = terms];
f[nmax = 2 nmax];
While[f[nmax] != f[nmax/2], nmax = 2 nmax];
seq = f[nmax] (* Jean-François Alcover, Dec 10 2021, after Ray Chandler in A003309 *)

Formula

(1-A010051(a(n)))*A192490(a(n)) = 1.