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A340140
a(1) = -1, for n > 1, a(n) = Sum_{d|n, d<n} A340197(n/d) * a(d).
4
-1, 0, 0, -2, 0, -7, 0, -6, -6, -13, 0, -13, 0, -19, -22, -22, 0, -19, 0, -23, -32, -31, 0, -81, -20, -37, -24, -33, 0, -21, 0, -78, -52, -49, -58, -183, 0, -55, -62, -147, 0, -29, 0, -53, -52, -67, 0, -321, -42, -53, -82, -63, 0, -223, -94, -213, -92, -85, 0, -591, 0, -91, -74, -278, -112, -45, 0, -83, -112, -45, 0, -733
OFFSET
1,4
COMMENTS
This seems to differ from 1-A318833(n) at the points given by A033987.
LINKS
FORMULA
a(1) = -1, for n > 1, a(n) = Sum_{d|n, d<n} A340197(n/d) * a(d).
PROG
(PARI)
A023900(n) = factorback(apply(p -> 1-p, factor(n)[, 1]));
A318833(n) = (n+A023900(n));
A340197(n) = if(1==n, 1, sumdiv(n, d, if(d<n, (A318833(n/d)-1)*A340197(d), 0)));
A340140(n) = if(1==n, -1, sumdiv(n, d, if(d<n, A340197(n/d)*A340140(d), 0)));
CROSSREFS
KEYWORD
sign,less
AUTHOR
Antti Karttunen, Jan 05 2021
STATUS
approved