A340140 a(1) = -1, for n > 1, a(n) = Sum_{d|n, dA340197(n/d) * a(d).

-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

Author

Antti Karttunen, Jan 05 2021

Keywords

• sign
• less

Comments

This seems to differ from 1-A318833(n) at the points given by A033987.

Links

• Antti Karttunen, Table of n, a(n) for n = 1..16384

Crossrefs

Cf. A023900, A033987, A318833, A340197, A340367.

Programs

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(dA318833(n/d)-1)*A340197(d),0)));
A340140(n) = if(1==n, -1, sumdiv(n, d, if(dA340197(n/d)*A340140(d), 0)));

Formula

a(1) = -1, for n > 1, a(n) = Sum_{d|n, dA340197(n/d) * a(d).