A184939 From the base sequence of the positive integers, keep the first two, remove the next three, keep the next five, remove the next seven, ..., block lengths determined by the prime numbers.
1, 2, 6, 7, 8, 9, 10, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 130, 131, 132
Offset: 1
Examples
In parentheses the blocks of integers removed: 1 2 (3 4 5) 6 7 8 9 10 (11 12 13 14 15 16 17) 18 19 20 21 22 23 24 25 26 27 28 (29 30 ...).
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Maple
L := [] ; p := 2 ; ptr := 1 ; while p < 40 do L := [op(L),seq(j,j=ptr..ptr+p-1)] ; ptr := ptr+p ; p := nextprime(p) ; ptr := ptr+p ; p := nextprime(p) ; end do: L ; # R. J. Mathar, Feb 08 2011 -
Mathematica
Module[{nn=20,t},t=Total[Prime[Range[nn]]];Take[TakeList[Range[t],Prime[ Range[nn]]],{1,nn,2}]]//Flatten (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 04 2019 *)
Comments