OFFSET
1,1
COMMENTS
This is one of six sequences that partition the positive integers. In general, suppose that r, s, t, u, v, w are positive real numbers for which the sets {i/r : i>=1}, {j/s : j>=1}, {k/t : k>=1}, {h/u : h>=1}, {p/v : p>=1}, {q/w : q>=1} are pairwise disjoint. Let a(n) be the rank of n/r when all the numbers in the six sets are jointly ranked. Define b(n), c(n), d(n), e(n), f(n) as the ranks of n/s, n/t, n/u, n/v, n/w respectively. It is easy to prove that
a(n) = n + [n*s/r] + [n*t/r] + [n*u/r] + [n*v/r] + [n*w/r],
b(n) = [n*r/s] + [n*t/s] + [n*u/s] + [n*v/s] + [n*w/s],
c(n) = [n*r/t] + [n*s/t] + [n*u/t] + [n*v/t] + [n*w/t],
d(n) = n + [n*r/u] + [n*s/u] + [n*t/u] + [n*v/u] + [n*w/u],
e(n) = n + [n*r/v] + [n*s/v] + [n*t/v] + [n*u/v] + [n*w/v],
f(n) = n + [n*r/w] + [n*s/w] + [n*t/w] + [n*u/w] + [n*v/w], where []=floor.
MATHEMATICA
x = Pi/8;
r = Sin[x]; s = Cos[x]; t = Tan[x]; u = 1/r; v = 1/s; w = 1/t;
p[n_, h_, k_] := Floor[n*h/k]
a[n_] := n + p[n, s, r] + p[n, t, r] + p[n, u, r] + p[n, v, r] + p[n, w, r]
b[n_] := n + p[n, r, s] + p[n, t, s] + p[n, u, s] + p[n, v, s] + p[n, w, s]
c[n_] := n + p[n, r, t] + p[n, s, t] + p[n, u, t] + p[n, v, t] + p[n, w, t]
d[n_] := n + p[n, r, u] + p[n, s, u] + p[n, t, u] + p[n, v, u] + p[n, w, u]
e[n_] := n + p[n, r, v] + p[n, s, v] + p[n, t, v] + p[n, u, v] + p[n, w, v]
f[n_] := n + p[n, r, w] + p[n, s, w] + p[n, t, w] + p[n, u, w] + p[n, v, w]
Table[a[n], {n, 1, 120}] (* A190739 *)
Table[b[n], {n, 1, 120}] (* A190740 *)
Table[c[n], {n, 1, 120}] (* A190741 *)
Table[d[n], {n, 1, 120}] (* A190742 *)
Table[e[n], {n, 1, 120}] (* A190743 *)
Table[f[n], {n, 1, 120}] (* A190744 *)
CROSSREFS
KEYWORD
nonn,changed
AUTHOR
Clark Kimberling, May 18 2011
STATUS
approved