OFFSET
1,2
COMMENTS
REFERENCES
Steven R. Finch, Mathematical Constants, Cambridge University Press, 2003, p. 15.
LINKS
Clark Kimberling, Table of n, a(n) for n = 1..1000
EXAMPLE
Let s(n) = log(3/2) - sum{1/(h*3^h), h = 1..n}. Approximations follow:
n ... s(n) ........ 1/6^n
1 ... 0.0721318 ... 0.166667
2 ... 0.0165762 ... 0.0277777
3 ... 0.0042305 ... 0.0046296
4 ... 0.0011441 ... 0.0007716
5 ... 0.0003210 ... 0.0001286
a(4) = 5 because s(5) < 1/6^4 < s(4).
MATHEMATICA
z = 300; p[k_] := p[k] = Sum[1/(h*3^h), {h, 1, k}];
N[Table[Log[3/2] - p[n], {n, 1, z/5}]]
f[n_] := f[n] = Select[Range[z], Log[3/2] - p[#] < 1/6^n &, 1];
u = Flatten[Table[f[n], {n, 1, z}]] (* A248562 *)
Flatten[Position[Differences[u], 1]] (* A248563 *)
Flatten[Position[Differences[u], 2]] (* A248564 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Oct 09 2014
STATUS
approved