OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
EXAMPLE
28 is in this sequence because its prime decomposition is 2^2* 7^1, it is not squarefree and the binary digits of "2" and "1" add up to 2, an even number.
MATHEMATICA
iMoebiusMu[ n_ ] := Switch[ MoebiusMu[ n ], 1, 1, -1, -1, 0, If[ OddQ[ Plus@@(DigitCount[ Last[ Transpose[ FactorInteger[ n ] ]], 2, 1 ]) ], -1, 1 ]]; Select[ Range[ 400 ], MoebiusMu[ # ]===0 && iMoebiusMu[ # ]===+1 & ]
PROG
(PARI) is(n)=my(f=factor(n)[, 2]); #f && vecmax(f)>1 && vecsum(apply(hammingweight, f))%2==0 \\ Charles R Greathouse IV, Oct 15 2015
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Wouter Meeussen, Dec 27 2001
STATUS
approved