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A334195
a(1) = 0, then after the first differences of A064415.
5
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
1,64
LINKS
FORMULA
a(1) = 0; and for n > 1, a(n) = A064415(n) - A064415(n-1).
a(n) = A334090(n) - A334091(n).
PROG
(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));
CROSSREFS
Also, from a(3) onward the first differences of A054725.
Sequence in context: A237621 A214625 A363339 * A348446 A279278 A015964
KEYWORD
sign
AUTHOR
Antti Karttunen, Apr 18 2020
STATUS
approved