A192503 Ludic prime numbers.

2, 3, 5, 7, 11, 13, 17, 23, 29, 37, 41, 43, 47, 53, 61, 67, 71, 83, 89, 97, 107, 127, 131, 149, 157, 173, 179, 181, 193, 211, 223, 227, 233, 239, 257, 277, 283, 307, 313, 331, 337, 353, 359, 383, 389, 397, 419, 421, 431, 433, 463, 467, 503, 509, 541, 577

Offset

1,1

Links

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

Formula

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

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 *)

Prog

(Haskell)
a192503 n = a192503_list !! (n-1)
a192503_list = filter ((== 1) . a010051) a003309_list
(PARI) A192503(maxn, bflag=0)={my(Vw=vector(maxn, x, x+1), Vl=Vec([1]), vwn=#Vw, i, vj, L=List());
while(vwn>0, i=Vw[1]; Vl=concat(Vl, [i]);
      Vw=vector((vwn*(i-1))\i, x, Vw[(x*i+i-2)\(i-1)]); vwn=#Vw);
kill(Vw); vwn=#Vl;
for(j=1, vwn, vj=Vl[j]; if(isprime(vj), listput(L, vj))); kill(Vw); vwn=#L;
if(bflag, for(i=1, vwn, print(i, " ", L[i]))); if(!bflag, return(Vec(L)));
} \\ Anatoly E. Voevudko, Feb 28 2016

Crossrefs

Intersection of A000040 and A003309.

Cf. A010051, A192490.

Cf. A192506 (neither ludic nor prime).

Sequence in context: A299956 A372629 A368732 * A040067 A181659 A040087

Adjacent sequences: A192500 A192501 A192502 * A192504 A192505 A192506

Keyword

nonn

Author

Reinhard Zumkeller, Jul 05 2011

Status

approved