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 A051916 The Greek sequence: 2^a * 3^b * 5^c where a = 0,1,2,3..., b,c in {0,1}, excluding the terms 1,2; that is: (a,b,c) =/= (0,0,0), (1,0,0)):. 8
 3, 4, 5, 6, 8, 10, 12, 15, 16, 20, 24, 30, 32, 40, 48, 60, 64, 80, 96, 120, 128, 160, 192, 240, 256, 320, 384, 480, 512, 640, 768, 960, 1024, 1280, 1536, 1920, 2048, 2560, 3072, 3840, 4096, 5120, 6144, 7680, 8192, 10240, 12288, 15360, 16384, 20480 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Contribution from Reinhard Zumkeller, Mar 19 2010: (Start) a(n+4) = 2*a(n) for n > 8; union of A007283, A020707, A020714, and A110286; intersection of A051037 and A003401 apart from terms 1 and 2. (End) REFERENCES George E. Martin: Geometric Constructions. New York: Springer, 1997, p. 140. LINKS R. Zumkeller, Table of n, a(n) for n = 1..1000 FORMULA G.f.: (3x^7+2x^6+2x^5+2x^4+6x^3+5x^2+4x+3)/(1-2x^4). MATHEMATICA CoefficientList[Series[(3x^7+2x^6+2x^5+2x^4+6x^3+5x^2+4x+3)/(1-2x^4), {x, 0, 60}], x] (* Harvey P. Dale, Dec 23 2012 *) PROG (PARI) Vec((3*x^7+2*x^6+2*x^5+2*x^4+6*x^3+5*x^2+4*x+3)/(1-2*x^4)+O(x^99)) \\ Charles R Greathouse IV, Oct 12 2012 CROSSREFS Sequence in context: A026506 A198382 A173946 * A130216 A120162 A002859 Adjacent sequences:  A051913 A051914 A051915 * A051917 A051918 A051919 KEYWORD nonn,easy,nice AUTHOR Antreas P. Hatzipolakis (xpolakis(AT)otenet.gr), Dec 17 1999 EXTENSIONS More terms from James A. Sellers, Dec 18 1999 Offset corrected by Reinhard Zumkeller, Mar 10 2010 STATUS approved

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Last modified June 5 12:47 EDT 2020. Contains 334840 sequences. (Running on oeis4.)