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 A005209 Multilevel sieve: at k-th step, accept k numbers, reject k, accept k, ... (Formerly M2792) 4
 1, 3, 9, 25, 57, 145, 337, 793, 1921, 3849, 8835, 18889, 41473, 92305, 203211, 432699, 944313, 2027529, 4077769, 8745153, 18133305, 37898113, 80713737, 169730259, 358760457, 750591867 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Start with the natural numbers. For k=1,2,3,... successively do the following: accept k numbers, reject k numbers, accept k numbers, repeat indefinitely. REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS N. J. A. Sloane, Table of n, a(n) for n = 1..1000 [Computed using Tom Duff's bc program] Popular Computing (Calabasas, CA), Contest 7 Results (based on solution from Tom Duff and Hugh Redelmeier), Vol. 4 (No. 43, Oct 1976), pp. 14-16. [Annotated scanned copy] PROG (bc) for(k=1; k<=100; k++){ n=k; for(i=k-1; i>=1; --i) n=2*n-((n-1)%i)-1; print k, " ", n, "\n" } /* Tom Duff, Apr 24 2015 */ CROSSREFS Sequence in context: A204448 A032681 A293852 * A112522 A005262 A101357 Adjacent sequences:  A005206 A005207 A005208 * A005210 A005211 A005212 KEYWORD nonn AUTHOR STATUS approved

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Last modified March 19 15:02 EDT 2019. Contains 321330 sequences. (Running on oeis4.)