OFFSET
1,1
COMMENTS
"omega(n)" (in the definition) means the number of prime factors of n counted without multiplicity, A001221. - Harvey P. Dale, Jul 14 2014
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..10000 (first 1369 terms from Robert Israel)
MAPLE
N:= 10^4: # to get all terms up to N
A:= [seq(numtheory[mobius](n), n=1..N)]:
Mertens:= map(round, Statistics:-CumulativeSum(A)):
omega:= t -> nops(numtheory:-factorset(t)):
select(t -> omega(t) = Mertens[t], [$1..N]); # Robert Israel, Jul 14 2014
MATHEMATICA
With[{nn=1000}, Flatten[Position[Thread[{Accumulate[Array[ MoebiusMu, nn]], PrimeNu[ Range[ nn]]}], _?(First[#]==Last[#]&), {1}, Heads->False]]] (* Harvey P. Dale, Jul 14 2014 *)
PROG
(PARI) isok(n) = (omega(n) == mertens(n)); \\ Michel Marcus, Sep 24 2013
(Haskell)
a067266 n = a067266_list !! (n-1)
a067266_list = filter (\x -> a001221 x == a002321 x) [1..]
-- Reinhard Zumkeller, Jul 14 2014
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Feb 21 2002
STATUS
approved