OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(2) = 35 because 35 = 5*7 is the least squarefree semiprime greater than and coprime to a(1) = 6.
MAPLE
A[1]:= 6: t:= 6: count:= 1:
for x from 7 while count < 100 do
if igcd(x, t) = 1 then
F:= ifactors(x)[2];
if nops(F) = 2 and F[.., 2] = [1, 1] then
count:= count+1;
A[count]:= x;
t:= x;
fi
fi
od:
seq(A[i], i=1..100);
MATHEMATICA
s={m1=6}; Do[If[ 2 == PrimeOmega[m] && SquareFreeQ[m] && CoprimeQ[m1, m], AppendTo[s, m1 = m]], {m, 7, 1000}]; s
lss[n_]:=Module[{k=n+1}, While[!SquareFreeQ[k]||PrimeOmega[k]!=2||!CoprimeQ[n, k], k++]; k]; NestList[lss, 6, 70] (* Harvey P. Dale, Dec 27 2023 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov and Robert Israel, Apr 17 2023
STATUS
approved