

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
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OFFSET

1,1


COMMENTS

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

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,0,2).


FORMULA

G.f.: x*(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).


MATHEMATICA

CoefficientList[Series[x(3x^7+2x^6+2x^5+2x^4+6x^3+5x^2+4x+3)/(12x^4), {x, 0, 60}], x] (* Harvey P. Dale, Dec 23 2012 *)


PROG

(PARI) Vec(x*(3*x^7+2*x^6+2*x^5+2*x^4+6*x^3+5*x^2+4*x+3)/(12*x^4)+O(x^99)) \\ Charles R Greathouse IV, Oct 12 2012


CROSSREFS

Cf. A003401, A007283, A020707, A020714, A051037, A110286.
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



