OFFSET
1,2
COMMENTS
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
FORMULA
Sum_{n>=1} 1/a(n) = 2.
MATHEMATICA
seq[m_] := Module[{v = {1}, r = 1, p = 3, k, n = m + 1, s = {1}, v1, s1, s2, rmax}, Do[AppendTo[v, p]; r *= 1 - 1/p; p = NextPrime[r/(r - 1/2)], {m}]; vmax = v[[-1]]; Do[v1 = v[[k]]; rmax = Floor[Log[vmax]/Log[v1]]; s1 = v1^Range[0, rmax]; s2 = Select[Union[Flatten[Outer[Times, s, s1]]], # <= vmax &]; s = Union[s, s2], {k, 2, n}]; s]; seq[5]
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Nov 30 2020
STATUS
approved