OFFSET
1,2
COMMENTS
k(31)>78496, k(32)=31545.
The first occurrence of k in A103668. - Robert G. Wilson v, May 07 2005
EXAMPLE
n=3, k=11, p(11)=31, p(12)=37, three semiprimes between 31 and 37 are 33=3*11, 34=2*17,35=5*7.
MATHEMATICA
fQ[n_] := Plus @@ Last /@ FactorInteger[n] == 2; f[n_] := Count[fQ /@ Range[Prime[n] + 1, Prime[n + 1] - 1], True];
t = Table[ f[n], {n, 1600000}]; Position[t, #, 1, 1] & /@ Range[0, 41] // Flatten (* Or *) t = Table[0, {50}]; Do[ a = f[n]; If[ t[[a + 1]] == 0, t[[a + 1]] = n], {n, 1600000}]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Zak Seidov, Feb 12 2005
EXTENSIONS
More terms from Robert G. Wilson v, May 07 2005
STATUS
approved