A334195 a(1) = 0, then after the first differences of A064415.

0, 1, 0, 1, 0, 0, 0, 1, -1, 1, 0, 0, 0, 0, 0, 1, 0, -1, 0, 1, -1, 1, 0, 0, 0, 0, -1, 1, 0, 0, 0, 1, -1, 1, -1, 0, 0, 0, 0, 1, 0, -1, 0, 1, -1, 1, 0, 0, -1, 1, 0, 0, 0, -1, 1, 0, -1, 1, 0, 0, 0, 0, -1, 2, -1, 0, 0, 1, -1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, -2, 2, 0, -1, 1, -1, 0, 1, 0, -1, 0, 1, -1, 1, -1, 1, 0, -1, 0, 1, 0, 0, 0, 0, -1

Offset: 1

Author

Antti Karttunen, Apr 18 2020

Keywords

• sign

Links

• Antti Karttunen, Table of n, a(n) for n = 1..65537

Crossrefs

Cf. A003434, A064415, A334090, A334091, A334196.

Also, from a(3) onward the first differences of A054725.

Programs

PARI

A003434(n) = for(k=0, n, n>1 || return(k); n=eulerphi(n));
A064415(n) = if(1==n,0, A003434(n)-(n%2));
A334195(n) = if(1==n,0,A064415(n)-A064415(n-1));

Formula

a(1) = 0; and for n > 1, a(n) = A064415(n) - A064415(n-1).

a(n) = A334090(n) - A334091(n).