A229205 Lucky numbers generated from squarefree numbers.

1, 3, 10, 13, 19, 22, 30, 33, 38, 47, 53, 59, 69, 71, 78, 82, 87, 97, 107, 110, 115, 129, 138, 146, 151, 158, 161, 167, 173, 182, 187, 197, 210, 218, 223, 227, 233, 249, 255, 265, 267, 278, 285, 295, 299, 305, 314, 318, 327, 334, 346, 357, 367

Offset: 1

Author

Irina Gerasimova, Sep 16 2013

Keywords

• nonn

Comments

Follow same procedure that is used to produce the lucky numbers A000959 but start with squarefree numbers A005117 instead of natural numbers.

Examples

			Start with squarefree numbers A005117 = (1, 2, 3, 5, 6, 7, 10, 11, 13, 14, 15, 17, 19, 21, 22, 23, 26, 29, 30,...).
Delete every second number to get (1,_ 3,_ 6,_ 10,_ 13,_ 15,_ 19,_ 22,_ 26,_ 30, ...).
Since the next larger remaining number is 3, delete every 3rd number, to get (1, 3,_ 10, 13,_ 19, 22,_ 30, ...).
The next larger remaining number is 10, so delete every 10th term, etc. Note that "30" will remain in this sequence, but is not among the squarefree numbers indexed by lucky numbers, A229483. - _M. F. Hasler_, Sep 24 2013
		

Crossrefs

Cf. A059987, A032605, A229483.

Programs

PARI

list_A229205(Nmax)={my(v=(select(issquarefree,vector(Nmax,i,i))),i,k);while(v[i=k+++(v[k]==1)]<=#v,v=vecextract(v,2^#v-1-sum(j=1,#v\v[i],2^(v[i]*j-1))));v} \\ M. F. Hasler, Sep 24 2013