A229205
Lucky numbers generated from squarefree numbers.
Original entry on oeis.org
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
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
-
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
A229483
Squarefree numbers whose indices are lucky numbers.
Original entry on oeis.org
1, 3, 10, 13, 19, 22, 33, 38, 47, 53, 59, 69, 78, 82, 102, 107, 110, 115, 119, 129, 141, 151, 161, 173, 182, 187, 206, 210, 215, 218, 227, 246, 258, 265, 274, 278, 309, 314, 318, 327, 334, 346, 359, 367, 382, 389, 391, 397, 426, 429, 437, 446, 462, 465, 470
Offset: 1
A229494
Lucky numbers generated from noncomposite numbers.
Original entry on oeis.org
1, 3, 13, 19, 37, 43, 61, 71, 89, 101, 113, 131, 163, 181, 193, 223, 229, 251, 281, 293, 317, 337, 359, 397, 409, 433, 443, 463, 479, 503, 521, 557, 569, 593, 601, 641, 701, 719, 743, 757, 787, 809, 839, 863, 911, 929, 953, 971, 997
Offset: 1
Start with noncomposite numbers A008578 = (1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, ...). Delete every 2nd number to get (1, 3, 7, 13, 19, 29, 37, ...). Since the next larger remaining number is 3, delete every 3rd term to get (1, 3, 13, 19, 37, ...). Then delete every 13th term, and so on.
-
list_A229494(N=200)={my(v=concat(1,primes(N)), i=1); until(v[i++]>#v, v=vecextract(v, 2^#v-1-sum(j=1, #v\v[i+(i<2)], 2^(v[i+(i<2)]*j-1)))); v}
Showing 1-3 of 3 results.
Comments