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 A100585 a(n+1) = a(n)+floor(a(n)/3), a(1) = 3. 11
 3, 4, 5, 6, 8, 10, 13, 17, 22, 29, 38, 50, 66, 88, 117, 156, 208, 277, 369, 492, 656, 874, 1165, 1553, 2070, 2760, 3680, 4906, 6541, 8721, 11628, 15504, 20672, 27562, 36749, 48998, 65330, 87106, 116141, 154854, 206472, 275296, 367061, 489414, 652552 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Original definition: Write down the numbers from 3 to infinity. Take next number, M say, that has not been crossed off. Counting through the numbers that have not yet been crossed off after that M, cross off every 4th term. Repeat, always crossing off every 4th term of those that remain. The numbers that are left form the sequence. LINKS Popular Computing (Calabasas, CA), Sieves: Problem 43, Vol. 2 (No. 13, Apr 1974), pp. 6-7. This is Sieve #6 with K=4. [Annotated and scanned copy] FORMULA a(1)=3, a(n+1) = a(n) + floor(a(n)/3). - Ben Paul Thurston, Jan 09 2008 MATHEMATICA t = Range[3, 2500000]; r = {}; While[Length[t] > 0, AppendTo[r, First[t]]; t = Drop[t, {1, -1, 4}]; ]; r (* Ray Chandler, Dec 02 2004 *) NestList[#+Floor[#/3]&, 3, 50] (* Harvey P. Dale, Jan 14 2019 *) PROG (PARI) a(n, s=3)=for(i=2, n, s+=s\3); s \\ M. F. Hasler, Oct 06 2014 CROSSREFS Cf. A003309, A003310, A100464, A100562, A003312, A003311, A052548, A100586. Sequence in context: A197639 A319314 A167057 * A023367 A291880 A047426 Adjacent sequences: A100582 A100583 A100584 * A100586 A100587 A100588 KEYWORD nonn AUTHOR N. J. A. Sloane, Dec 01 2004 EXTENSIONS More terms from Ray Chandler, Dec 02 2004 Simpler definition from M. F. Hasler, Oct 06 2014 STATUS approved

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Last modified December 3 09:50 EST 2022. Contains 358517 sequences. (Running on oeis4.)