OFFSET
1,1
LINKS
David A. Corneth, Table of n, a(n) for n = 1..10000
FORMULA
a(1) = A087978(3).
EXAMPLE
1042404 = 2^2*3*11*53*149, 1042405 = 5*6*143*29*79 and 1042406 = 2*17*23*31*43 each have 5 distinct prime factors, so 1042404 is in the sequence.
MAPLE
omega := proc(n)
nops(numtheory[factorset](n)) ;
end proc:
for k from 1 do
if omega(k) = 5 then
if omega(k+1) = 5 then
if omega(k+2) = 5 then
print(k) ;
end if;
end if;
end if;
end do:
MATHEMATICA
seq[lim_] := Module[{s = {}, q1 = False, q2 = False, q3}, Do[q3 = PrimeNu[k] == 5; If[q1 && q2 && q3, AppendTo[s, k-2]]; q1 = q2; q2 = q3, {k, 3, lim}]; s]; seq[10^7] (* Amiram Eldar, Oct 01 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
R. J. Mathar, Jul 16 2023
STATUS
approved