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A005658 If n appears so do 2n, 3n+2, 6n+3.
(Formerly M0969)
+0
2
1, 2, 4, 5, 8, 9, 10, 14, 15, 16, 17, 18, 20, 26, 27, 28, 29, 30, 32, 33, 34, 36, 40, 44, 47, 50, 51, 52, 53, 54, 56, 57, 58, 60, 62, 63, 64, 66, 68, 72, 80, 83, 86, 87, 88, 89, 92, 93, 94, 98, 99, 100, 101, 102, 104, 105, 106, 108, 110, 111, 112, 114, 116, 120, 122, 123 (list; graph; listen)
OFFSET

1,2

COMMENT

David Klarner and coauthors studied several sequences of this type. Some of the references here apply generally to this class of sequences.

REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

R. K. Guy, Don't try to solve these problems, Amer. Math. Monthly, 90 (1983), 35-41.

Guy, R. K., Klarner-Rado Sequences. Section E36 in Unsolved Problems in Number Theory, 2nd ed. New York: Springer-Verlag, p. 237, 1994.

Hoffman, D. G. and Klarner, D. A. Sets of integers closed under affine operators-the finite basis theorem. Pacific J. Math. 83 (1979), no. 1, 135-144.

Hoffman, D. G. and Klarner, D. A. Sets of integers closed under affine operators-the closure of finite sets. Pacific J. Math. 78 (1978), no. 2, 337-344.

Klarner, David A., m-Recognizability of sets closed under certain affine functions. Discrete Appl. Math. 21 (1988), no. 3, 207-214.

Klarner, David A. and Post, Karel Some fascinating integer sequences. A collection of contributions in honour of Jack van Lint. Discrete Math. 106/107 (1992), 303-309.

Klarner, D. A. and Rado, R. Arithmetic properties of certain recursively defined sets. Pacific J. Math. 53 (1974), 445-463.

LINKS

R. J. Mathar, Table of n, a(n) for n = 1..15889

Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.

PROGRAM

(C++) #include <stdio.h> #include <iostream> #include <set> using namespace std ; int main(int argc, char *argv[]) { const int anmax= 40000 ; set<int> a ; a.insert(1) ; for(int i=0; i< anmax ; i++) { if( a.count(i) ) { if( 2*i<=anmax) a.insert(2*i) ; if( 3*i+2 <= anmax) a.insert(3*i+2) ; if( 6*i+3 <= anmax) a.insert(6*i+3) ; } } int n=1 ; for(int i=0; i < anmax; i++) { if( a.count(i) ) { cout << n << " " << i << endl ; n++ ; } } return 0 ; } - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 20 2006

CROSSREFS

Sequence in context: A069011 A101185 A045702 this_sequence A166021 A003714 A010402

Adjacent sequences: A005655 A005656 A005657 this_sequence A005659 A005660 A005661

KEYWORD

nonn,easy,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Oct 16 2000

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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