The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A108696 Generated by a sieve: see comments. 4
 1, 2, 3, 5, 7, 11, 13, 19, 23, 31, 35, 43, 49, 59, 61, 79, 83, 103, 109, 119, 133, 151, 155, 175, 193, 211, 215, 241, 259, 275, 283, 323, 331, 361, 373, 403, 419, 443, 455, 499, 511, 541, 571, 613, 623, 649, 673, 719, 733, 781, 803, 841, 871, 919 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Start with the natural numbers: 1 2 3 4 5 6 7 8 9 10 11 ... Accept the 2nd number, 2 and erase every 2nd number after it, giving: 1 2 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 ... Accept the 3rd number, 3 and erase every 3rd number after it, giving: 1 2 3 5 7 11 13 17 19 23 25 29 31 35 ... Accept the 4th number, 5 and erase every 4th number after it, giving: 1 2 3 5 7 11 13 19 23 25 31 35 ... Repeat! LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 PROG (tcl) source /tclutils/utils.tcl set l [range 0 10000]; set z z for {set i 2} {\$i*2 <= [llength \$l]} {incr i} { set k [expr {[llength \$l]-1}] set k [expr {\$k - (\$k % \$i)}] while {\$k > \$i} { set l [lreplace \$l \$k \$k] incr k -\$i } puts "after \$i: length [llength \$l], prefix [join [lrange \$l 0 10] { }]" } (Haskell) a108696 n = a108696_list !! (n-1) a108696_list = 1 : sieve' 2 [2..] where    sieve' n (x:xs) = x : (sieve' (n+1) \$ sieving xs) where       sieving xs = (take (n-1) xs) ++ (sieving \$ drop n xs) -- Reinhard Zumkeller, Jul 04 2011 CROSSREFS Equals A007952 + 2 or equally A002491(n) + 1. Sequence in context: A233893 A232824 A078334 * A215642 A092581 A130807 Adjacent sequences:  A108693 A108694 A108695 * A108697 A108698 A108699 KEYWORD nonn AUTHOR David Applegate, Oct 11 2007 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 14 03:53 EDT 2021. Contains 342941 sequences. (Running on oeis4.)