OFFSET
1,1
MATHEMATICA
A321516[n_] := Length[Select[Most[Divisors[n]], CompositeQ]]; abQ[n_] := DivisorSum[n, Total[IntegerDigits[#, 2]]*(-1)^Boole[#==n]&]>0; A294902[n_] := Length[Select[Most[Divisors[n]], abQ[#] &]]; Select[Range[650], A321516[#] != A294902 [#] &] (* Amiram Eldar, Nov 12 2018 after Jean-François Alcover at A175526 *)
PROG
(PARI) a292257(n) = sumdiv(n, d, (d<n)*hammingweight(d)) \\ after Antti Karttunen in A292257
a294905(n) = (a292257(n) <= hammingweight(n)) \\ after Antti Karttunen in A294905
a294902(n) = sumdiv(n, d, (d<n)*(0==a294905(d))) \\ after Antti Karttunen in A294902
a321516(n) = my(d=divisors(n), i=0); for(k=2, #d-1, if(!ispseudoprime(d[k]), i++)); i
is(n) = a294902(n)!=a321516(n)
CROSSREFS
KEYWORD
nonn
AUTHOR
Felix Fröhlich, Nov 12 2018
STATUS
approved