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A184916
n+[sn/r]+[tn/r]+[un/r], where []=floor and r=1, s=2^(1/4), t=s^2, u=s^3.
7
4, 9, 15, 19, 25, 31, 35, 41, 46, 51, 57, 62, 67, 72, 78, 83, 89, 94, 98, 104, 109, 115, 120, 125, 131, 135, 142, 147, 152, 157, 162, 168, 173, 179, 183, 188, 195, 199, 205, 210, 214, 220, 226, 231, 236, 242, 247, 252, 258, 263, 268, 273, 279, 284, 289, 295, 299, 305, 311, 315, 321, 326, 331, 337, 342, 347, 352, 358, 364, 368, 374, 379, 384, 390, 396, 400, 405, 411, 415, 422, 427, 431, 437, 442, 448, 453, 459, 463, 468, 475, 480, 485, 490, 495, 500, 506, 512, 516, 522, 527, 532, 538, 543, 548, 553, 559, 564, 569, 575, 579, 585, 591, 596, 601, 606, 612, 617, 622, 628, 632
OFFSET
1,1
COMMENTS
The sequences A184916-A184919 partition the positive integers:
A184916: 4,9,15,19,25,31,35,41,...
A184917: 3,7,12,16,21,26,29,34,...
A184918: 2,6,10,13,17,22,24,28,...
A184919: 1,5,8,11,14,18,20,23,27,...
The joint ranking method of A184812 is extended here to four numbers r,s,t,u, as follows: jointly rank the sets {h*r}, {i*s}, {j*t}, {k*u}, h>=1, i>=1, j>=1, k>=1.
The position of n*r in the joint ranking is
n+[sn/r]+[tn/r]+[un/r], and likewise for the
positions of n*s, n*t, and n*u.
FORMULA
a(n)=n+[sn/r]+[tn/r]+[un/r], where []=floor and
r=1, s=2^(1/4), t=s^2, u=s^3.
MATHEMATICA
r=1; s=2^(1/4); t=2^(1/2); u=2^(3/4);
a[n_]:=n+Floor[n*s/r]+Floor[n*t/r]+Floor[n*u/r];
b[n_]:=n+Floor[n*r/s]+Floor[n*t/s]+Floor[n*u/s];
c[n_]:=n+Floor[n*r/t]+Floor[n*s/t]+Floor[n*u/t];
d[n_]:=n+Floor[n*r/u]+Floor[n*s/u]+Floor[n*t/u];
Table[a[n], {n, 1, 120}] (* A184916 *)
Table[b[n], {n, 1, 120}] (* A184917 *)
Table[c[n], {n, 1, 120}] (* A184918 *)
Table[d[n], {n, 1, 120}] (* A184919 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Jan 26 2011
STATUS
approved