A249876 Pseudo-lucky numbers.

1, 3, 5, 7, 11, 13, 17, 21, 23, 25, 31, 35, 41, 43, 45, 47, 55, 57, 63, 65, 73, 75, 83, 87, 95, 97, 101, 105, 107, 113, 123, 127, 131, 133, 141, 143, 147, 151, 153, 161, 175, 177, 183, 185, 197, 201, 211, 213, 215, 217, 227, 233, 235, 237, 251, 255, 265, 267

Offset: 1

Author

Robert FERREOL, Nov 07 2014

Keywords

• nonn

Comments

Appears to grow more slowly than the Lucky numbers. - Jon Perry, Nov 07 2014

Examples

			Start with the natural numbers. The 2nd number is 2, so delete every 2nd number, leaving 1 3 5 7 9 11 13 15 17 19...; the 3rd number remaining is 5, so delete every 5th number, leaving 1 3 5 7 11 13 15 17 ...; now delete every 7th number, leaving 1 3 5 7 11 13 17 ...; now delete every 11th number; etc.
		

Links

• Jean-François Alcover, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A000959 (Lucky numbers).

Programs

Maple

L:= [seq(i, i=1..10^3)]:
for n from 2 while n < nops(L) do
  r:= L[n];
  L:= subsop(seq(r*i=NULL, i=1..nops(L)/r), L);
od:
L;

Mathematica

FixedPoint[Function[{L}, n++; Delete[L, List /@ (L[[n]]*Range[Quotient[Length[L], L[[n]] ]])]], n=1; Range[1000]] (* Jean-François Alcover, Nov 27 2014 *)

Python

def listed(n):
   L=list(range(1,n+1));j=1
   while L[j] <= len(L):
      L=[L[i] for i in range(len(L)) if (i+1)%L[j]!=0]
      j+=1
   return(L)