OFFSET
1,1
COMMENTS
Semiprimes in arithmetic progression. All terms are odd, see also A056809.
LINKS
Robert Israel, Table of n, a(n) for n = 1..2000
MAPLE
R:= NULL:
state:= 0: count:= 0:
for n from 1 by 2 while count < 40 do
if numtheory:-bigomega(n) = 2 then state:= state+1
else state:= 0
fi;
if state >= 6 then R:= R, n - 10; count:= count+1; fi
od:
R; # Robert Israel, Sep 11 2025
MATHEMATICA
PrimeFactorExponentsAdded[n_] := Plus @@ Flatten[Table[ #[[2]], {1}] & /@ FactorInteger[n]]; Select[ Range[ 99210], PrimeFactorExponentsAdded[ # ] == PrimeFactorExponentsAdded[ # + 2] == PrimeFactorExponentsAdded[ # + 4] == PrimeFactorExponentsAdded[ # + 6] == PrimeFactorExponentsAdded[ # + 8] == PrimeFactorExponentsAdded[ # + 10] == 2 &] (* Robert G. Wilson v, Feb 24 2004 *)
spQ[n_]:=PrimeOmega[n]==2; Select[Range[100000], AllTrue[#+{0, 2, 4, 6, 8, 10}, spQ]&] (* Harvey P. Dale, Dec 19 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Feb 22 2004
EXTENSIONS
More terms from Don Reble, Feb 23 2004
More terms from Robert G. Wilson v, Feb 24 2004
STATUS
approved