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A184534
a(n) = floor(1/{(4+n^3)^(1/3)}), where {}=fractional part.
2
1, 3, 7, 12, 18, 27, 36, 48, 60, 75, 90, 108, 126, 147, 168, 192, 216, 243, 270, 300, 330, 363, 396, 432, 468, 507, 546, 588, 630, 675, 720, 768, 816, 867, 918, 972, 1026, 1083, 1140, 1200, 1260, 1323, 1386, 1452, 1518, 1587, 1656, 1728, 1800, 1875, 1950, 2028, 2106, 2187, 2268, 2352, 2436, 2523, 2610, 2700, 2790, 2883, 2976, 3072, 3168, 3267, 3366, 3468, 3570, 3675, 3780, 3888, 3996, 4107, 4218, 4332, 4446, 4563, 4680, 4800, 4920, 5043, 5166, 5292, 5418, 5547, 5676, 5808
OFFSET
1,2
LINKS
FORMULA
a(n) = floor[1/{(4+n^3)^(1/3)}], where {}=fractional part.
a(n) = 2*a(n-1) - 2*a(n-3) + a(n-4).
From Colin Barker, Oct 07 2012: (Start)
Empirical: a(n) = 3*(1 - (-1)^n + 4*n + 2*n^2)/8 for n>2.
Empirical G.f.: x*(x^6-2*x^5+x^4-x^2-x-1)/((x-1)^3*(x+1)).(End)
MATHEMATICA
Table[Floor[1/FractionalPart[(n^3 + 4)^(1/3)]], {n, 1, 120}]
PROG
(PARI) for(n=1, 50, print1(floor(1/frac((4 + n^3)^(1/3))), ", ")) \\ G. C. Greubel, May 14 2017
CROSSREFS
Sequence in context: A122250 A169679 A024388 * A109638 A008332 A065390
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 16 2011
STATUS
approved