

A138007


Produced by a sieve: Start with the natural numbers; at the kth step remove every A138008(k+1)th term of the sequence remaining after the (k1)st sieving step.


2



1, 2, 4, 5, 8, 10, 11, 13, 17, 19, 20, 23, 26, 28, 31, 34, 38, 40, 43, 46, 47, 50, 55, 56, 58, 61, 64, 68, 71, 76, 77, 80, 85, 86, 92, 94, 95, 98, 101, 103, 106, 109, 115, 118, 122, 124, 125, 128, 137
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OFFSET

1,2


COMMENTS

The sequence A138008 is defined using this sequence, in the same way as A138008 is used to define this sequence.
The sequences can be found this way:
Define a(n,1)=n.
Now write the natural numbers and run this sieve: In the kth step remove every a(k+1,1)th number that remained after k1 step. You will get this:
1, 3, 7, 13, 19, ... (A000960).
Now let a(n,2) be nth number in this sequence.
In the same way: Define a(n,i+1) to be the nth number left after running the similar sieve on the natural numbers using a(n,i) instead of a(n,1). Now:
a(n,2i+1)> A138007(n) when i>infinity and,
a(n,2i)> A138008(n) when i>infinity.


LINKS

Table of n, a(n) for n=1..49.


EXAMPLE

Start with the natural numbers:
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, ...
Remove every A138008(2)=3rd term:
1, 2, 4, 5, 7, 8, 10, 11, 13, 14, 16, 17, 19, 20, ...
Remove every A138008(3)=5th term:
1, 2, 4, 5, 8, 10, 11, 13, 16, 17, 19, 20, ...
Remove every A138008(4)=9th term:
1, 2, 4, 5, 8, 10, 11, 13, 17, 19, 20, ...
and so on.


CROSSREFS

Cf. A138008.
Sequence in context: A185392 A324700 A191987 * A284880 A047261 A286687
Adjacent sequences: A138004 A138005 A138006 * A138008 A138009 A138010


KEYWORD

nonn


AUTHOR

Sune Kristian Jakobsen (sunejakobsen(AT)hotmail.com), Feb 27 2008


STATUS

approved



