A184534 a(n) = floor(1/{(4+n^3)^(1/3)}), where {}=fractional part.

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

G. C. Greubel, Table of n, a(n) for n = 1..1000

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

Cf. A183532, A183534.

Sequence in context: A122250 A169679 A024388 * A109638 A008332 A065390

Adjacent sequences: A184531 A184532 A184533 * A184535 A184536 A184537

Keyword

nonn

Author

Clark Kimberling, Jan 16 2011

Status

approved