OFFSET
1,6
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..4137
MATHEMATICA
Array[If[# == 1, 0, Function[n, DivisorSum[n, MoebiusMu[n/#] (2 # - DigitCount[2 #, 2, 1] - DivisorSigma[1, #]) &]]@ Floor@ Total@ Flatten@ MapIndexed[#1 2^(#2 - 1) &, Flatten[Table[2^(PrimePi@ #1 - 1), {#2}] & @@@ FactorInteger@ #]]] &, 90] (* Michael De Vlieger, Mar 11 2019 *)
PROG
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Mar 05 2019
STATUS
approved